Prince William encouraged the Archbishop of Canterbury to seek help for depression

Justin Welby has credited his friendship with the Duke of Cambridge with helping him through dark times (Getty Images)

He has opened up about his own issues with mental health in the past - and now Prince William has been credited by the Archbishop of Canterbury with encouraging him to also seek help.

Justin Welby, 64, has revealed that his friendship with the Duke of Cambridge, 38, helped when he was “struggling”.

Writing in The Sunday Times, he explained: “I am deeply grateful to His Royal Highness for speaking publicly about mental health and hope it might encourage others who are suffering alone to seek help and support.

“It encouraged me to seek help when I was struggling, help which was effective.”

Justin Welby has long been close to the Duke of Cambridge (pictured at Prince Harry's wedding to Meghan Markle in 2018) (Getty Images)

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Welby is understood to have spoken to both the father-of-three and his younger brother Prince Harry, 35, about his battle with depression.

Similarly, the dukes are believed to have in turn spoken to him about their own mental health.

The archbishop baptised their children - Prince George, Princess Charlotte and Prince Louis, as well as Archie - and also officiated at the wedding of the Duke of Sussex to Meghan Markle in 2018.

He has opened up about dealing with the “black dog”, and said “I have those moments...when objectively everything is fine, but you think you are, beyond description, hopeless”.

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Acknowledging he needed outside assistance, Welby has revealed he sought professional help and has taken medication.

The archbishop revealed that he experienced a “noisy, disturbed childhood” while being raised by alcoholic, divorced parents.

In 2016, he discovered that his biological father was not Gavin Welby, but Sir Anthony Montague Browne, a private secretary to Winston Churchill.

His comments come after the Duke of Cambridge spoke about how the Christian Christian faith can help people navigate “through uncertain times”.

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The future head of the Church of England recorded a “refection” for the church’s streamed service today to mark the end of mental health awareness week.

He said: “I want to encourage anyone who has concerns about their own mental health, or that of others, to reach out.

“For some that may be through prayer and quiet reflection; for others it could be talking to a fellow parishioner, friend or family member about how they are feeling.

“Whoever you talk to...finding the words to open up can be a life-changing step.”

The duke has been self-isolating in his country home Anmer Hall of Norfolk, on the Queen’s Sandringham Estate, with Kate Middleton and their three children.