Mollie King has updated fans on how she is coping with the "heartache" after losing her dad to brain cancer, sharing that "the nights are the hardest".

The Saturdays star and radio presenter, 35, has decided to open up about her grief, rather than just continuing to "keep as busy as possible" to distract herself, in support of Brain Tumour Awareness Month.

King's father was diagnosed with the disease in August last year and sadly passed away three months later.

Read more: New mum’s 'excruciating migraines' turned out to be a fast-growing brain tumour

Accompanied with a picture of her and her dad taking a selfie, smiling together, King's caption reads, "This month is Brain Tumour Awareness month. I’ve always tried not to let myself think about losing someone I love, it’s too hard to think about, but last year this fear became a reality.

"In August my wonderful Dad was diagnosed with a brain tumour and we had to say goodbye to him just 3 months later. It’s still very hard to write about, I’ve been putting off writing this post because it’s easier to push it to the back of my mind and try to keep as busy as possible to cover up the heartache."

King also paid a tribute to "the best Dad you could ask for", expressing she is "so thankful" he got to hold her baby daughter Annabella, who "he would have adored".

"For anyone who has lost someone, you might agree that the nights are the hardest, and talking about him in the past tense is something I hate doing," she adds.

"Dad’s life was cut short and his diagnosis came completely out of the blue - he was out walking Alfie with me the morning that everything changed. Dad was incredibly active, he ran 3 marathons and walked in Richmond Park almost every day. He had so much life left to live."

Read more: Man with incurable brain tumour outlives his five-year prognosis to find love

Sharing that her family "have been utterly heartbroken by what this horrible disease did" to her Dad, King says they want to raise awareness and funds for The Brain Tumour Charity, for which her sister Laura is running the London Marathon in April (the sponsorship link is in Mollie's Instagram Stories).

"Our lives will never be the same after losing our beloved Dad and our love and thoughts go out to anyone whose life has also been touched by cancer."

King's celebrity friends showed their support in the comments, including former bandmate Una Healy who wrote, "So beautifully written Mollie, sending you and all of your family so much love", and Nicki Chapman who said, "I’m so sorry for your loss Mollie. This fantastic charity helped me enormously after my brain tumour surgery".

The star first paid a heartfelt tribute to her dad after his death, sharing that he "held on a few extra days" to meet Annabella, who she and cricketer fiancé Stuart Broad publicly welcomed a week prior.

She posted a series of pictures with her father to Instagram on Wednesday 30 November, announcing the news.

King wrote, "Heartbroken beyond words. In August, my family’s world was shattered when my Dad was diagnosed with a brain tumour. Last week, we had to face the day we hoped would never come and say goodbye.

"Dad, we love you with all our hearts and we will miss you every single day. You have been our hero and it’s impossible to think of our lives without you. You have always been there for us with every step we’ve taken and you even held on a few extra days to meet baby Annabella.

"You gave us your everything. You will be in our hearts and our memories every single day."

Many also showed their support and wrote messages of condolences in the comments too.

Bandmate Frankie Bridge wrote, "Love you xxx', as one of the first, while Una Healy, who was also in The Saturdays, said, "I’m so sorry for your loss, he was such an amazing Dad and person. Love you so much. May he R.I.P."

Meanwhile, Amanda Holden commented, "So sorry darling", Giovanna Fletcher, "Oh Mollie, I’m so sorry to read this. Sending you and your family so much love!! Xxxx", and Clara Amfo, "Sending infinite love Mollie, so glad he got to meet your girl xx."

Ruth Langsford also wrote, "Oh darling Mollie… I am so, so sorry to hear about your darling Dad passing. Sending you and your family so much love. Grief is the price we pay for love. Hold all your memories close… nothing can take those away. Love you darling."

Jess Wright, Alexandra Burke, Emily Atack, Laura Whitmore, Gethin Jones, Zoe Ball, and many more also offered their support, including fans.

Read more: 'There is no instruction manual': How to cope with grief

Grief is something that will affect us all at some point in our lives, with the five stages thought to be 'denial', 'anger', 'bargaining', 'depression' and then 'acceptance'.

"The five stages of grief are thought of as a kind of road map that helps us recognise the types of feelings that we have when we're grieving and the purpose of all these feelings," leading psychotherapist and bestselling author Julia Samuel previously told Yahoo Life UK. "Many people find these five stages very helpful because they recognise themselves in them."

"These stages are part of a natural adaptive process," added Samuel. "By allowing ourselves to really feel the grief in all these different ways – missing the person, yearning, being sad or being angry – we are adaptive and grief when it's healthy is also adaptive."

Brain tumours can seem like one of the most scary health conditions, but thankfully more is being done to raise awareness, including through the recent Lola Pearce storyline on EastEnders.

In October, the late Tom Parker's widow Kelsey also called for more funding into brain tumour research in the UK, after The Wanted singer died at a hospice near the couple’s south-east London home on 30 March at the age of 33, following his diagnosis with stage four glioblastoma.

Early detection is key. Here's what you need to know about brain tumours.

Read more: 'I had life-saving surgery for a brain tumour but it wiped all my childhood memories'

What are brain tumours?

A brain tumour is a growth of cells in the brain that 'multiplies' in an abnormal, uncontrollable way, according to the NHS. There are different 'grades', including one and two that are low grade, and three and four that are high grade.

The two main types of brain tumours are non-cancerous (benign), which are low grade and grow slowly and are less likely to return after treatment.

Cancerous (malignant), meanwhile, are high grade and either start in the brain (primary tumours) or spread into the brain from elsewhere (secondary). These are more likely to grow back after treatment.

What are the symptoms of a brain tumour?

The symptoms of a brain tumour will depend upon which part of the brain is affected, according to Brain Tumour Research.

The most common symptoms are caused by an increase in pressure in the skull prompted by the growth of a tumour in the brain.

Other likely symptoms, which may initially come and go, can include one or more of the following:

• Headaches

• Eye and vision-related problems (such as squinting and double-vision)

• Continuing nausea, vomiting

• Extreme or sudden drowsiness

• Tinnitus (ringing in the ears) or hearing loss

• Unexplained twitches of the face or limbs

• Seizures (fits or faints)

• Appearing to be lost in a deep daydream for a short while

• Confusion

• Loss of balance

• Numbness or weakness in the arms or legs, especially if progressive and leading to paralysis

• Numbness or weakness in a part of the face, so that the muscles drop slightly

• Numbness or weakness on one side of the body, resulting in stumbling or lack of co-ordination

• Changes in personality or behaviour

• Impaired memory or mental ability, which may be very subtle to begin with

• Changes in senses, including smell

• Problems with speech, writing or drawing

• Loss of concentration or difficulty in concentrating

• Changes in sleep patterns

Read more: Woman's 'déjà vu' turned out to be a symptom of a brain tumour

“Depending on which part of the brain the tumour is affecting, the symptoms can vary,” Dr Daniel Cichi from Doctor 4 U adds. “If, for instance, a tumour is located at the frontal lobes this may cause personality and behavioural changes.

“Symptoms can vary greatly amongst patients, but in general, any noticeable changes to your behaviour, mobility, vision or speech should be checked out by your doctor.”

Dr Cichi says that in particular, if you’re experiencing frequent and severe headaches, loss of sensation or movement in your limbs that happens gradually, or progressive weakness on one side of the body, as well as seizures or speech and vision problems, these could indicate a brain tumour. But, he cautions, it’s not always the case.

“Nausea, vomiting, drowsiness and headaches may be the more subtle signs of a brain tumour as many people put these symptoms down to tiredness, working too hard, or other illnesses,” he adds.

“But anyone who is experiencing headaches which are out of the ordinary for them should speak to their GP as soon as possible.”

Watch: Woman loses all her childhood memories after life saving surgery to remove brain tumour

Brain tumour treatments

As mentioned above, not all brain tumours are cancerous and some are less complicated than others, depending on where the tumour is located, among other things.

“Non-cancerous tumours can often be removed successfully with surgery and they very rarely grow back,” Dr Cichi explains.

“In some cases, a person may be able to live with their benign tumour for quite some time before they have surgery because they are slow-growing compared to cancerous tumours which grow at a much faster rate.”

Cancerous brain tumours can also be treated with surgery, as well as radiotherapy and chemotherapy if not all of the tumour could be removed in surgery.

“Different types of speech and physical therapy may be given if the tumour has affected motor skills, vision, and speech,” Dr Cichi adds.

What causes brain tumours?

Often, the cause of a brain tumour is unknown, but according to Dr Cichi they're more likely to develop in old age.

While most happen in 85 to 89-year-olds, they can affect people of any age, including children.

“Genetics (family history) can also play a part, and we know that exposure to radiation can increase the risk of developing some types of brain tumours,” he adds.

While this only accounts for a small number of brain tumours, some types are more common in those who have had radiotherapy, CT scans, or X-rays of the head.

What is glioblastoma?

Glioblastoma multiforme (GBM), the type of brain tumour Parker had (and Lola on EastEnders), is the most common type of brain tumour that starts in the brain.

According to The Brain Tumour Charity, it is the most aggressive form of adult brain tumour and is often resistant to treatment.

It is believed that the variety of cells in a glioblastoma is one of the reasons it is so hard to treat, because current drugs are not able to effectively target all the cell types in the tumour.

As with most brain tumours, the cause of glioblastoma is not known.

Read more: Tom Parker used cannabis as pain relief, The Wanted star's posthumous autobiography reveals

Brain Tumour Research says the first option for the treatment of GBM, if the tumour is operable, is surgery, usually followed by radiotherapy and chemotherapy.

“The surgical operation to remove a GBM is a delicate balancing act between removing as much of the tumour as possible and protecting the function of the healthy brain,” says a spokesperson for Brain Tumour Research.

“So the location of the brain tumour is very important with regard to both the potential impact of surgery and the symptoms that the patient will experience (because different areas of the brain control different mental and physical processes).”

How much of a glioblastoma a neurosurgeon can remove is limited because GBMs are 'diffuse', meaning that tumour cells invade healthy areas of the brain adjacent to the tumour.

Unfortunately, the nature of GBM means some tumour cells will almost always be left behind and hence will continue to grow.

For this reason, radiotherapy and chemotherapy are the next stages of treatment for a GBM. Usually, people are offered the chemotherapy drug Temozolomide (TMZ) alongside radiotherapy, and then further doses of Temozolomide afterwards.

For more information visit the NHS's website page on brain tumours.

You or your loved one being diagnosed with brain tumour can be frightening. But as well as your doctors and medical professionals being there to guide you through it, further support is out there too – visit The Brain Tumour Charity's website or call its helpline on 0808 800 0004.