The long-awaited vaccine arrived in GP practices across England on Monday, with those over the age of 80, NHS and care home staff receiving top priority.
McKellen posed for photos while receiving the first of his two jabs, admitting it was a “very special day.”
He added: “Anyone who has lived as long as I have is alive because they have had previous vaccinations, the take up amongst the older generation will be 100 per cent - it ought to be - because you're having it not just for yourself but for people who you are close to - you're doing your bit for society.
"Of course, it's painless... it's convenient, and getting in touch and meeting NHS staff and saying thank you to them for how hard they've been working is a bonus, I would have no hesitation in recommending it to anyone.”
Two jabs are needed for the recipient to gain immunity from Covid-19, with an interval of three weeks required between injections.
McKellen joins the likes of musician Marty Wilde, 81, showbiz veteran Lionel Blair, 92, and Bake Off judge Prue Leith, 80, who also received the vaccine earlier this week.
Leith shared a photo of the procedure on Twitter on Tuesday, writing: “Who wouldn't want immunity from #Covid19 with a painless jab?? #vaccine.”
Prime minister Boris Johnson praised Leith for getting vaccinated, tweeting: "Great news Prue! Wonderful to see so many in the UK getting vaccinated.
“Many thanks to the health workers who are working tirelessly to get this vaccine to people up and down the country.”
The Pfizer-BioNTech vaccine was approved on Wednesday 2 December and rolled out across the UK on Tuesday 8 December, with grandmother Margaret Keenan - who turns 91 this week - being the first person in the world to be given the jab.
The vaccine, which is thought to be 95 per cent effective, is part of the biggest vaccination programme in the UK's history.