Benedict Cumberbatch turned 40 on Tuesday July 19.
Such a landmark age might be difficult to put to the uniquely handsome British actor, not least because of his relatively late start to superstardom - he didn't become a global household name until 2010 when he took on the leading role in the BBC's Sherlock.
Not only that, but he has an appearance that defies all signs of ageing, with barely a line upon his expressive face.
The famously down-to-earth gent has achieved plenty in his 40 years on earth: he's scored plenty of top roles in films such as 12 Years A Slave, The Hobbit: The Desolation Of Smaug and Tinker Tailor Soldier Spy, he's been nominated for an Oscar for his role in The Imitation Game and also a handful of Baftas, he was made a CBE in 2015 and he's also quite the cult icon on the internet. This year he also became a first-time father with his wife of just over one year, Sophie Hunter.
However, the British stage and screen star isn't the only famous person whose age is quite the surprise.
Check out these other seven stars who are also 40 years old - whether you think they seem older or younger is up to you.
Kate Winslet turned 40 on October 5 last year, and it's fair to say the Oscar-winning actress has achieved more in her lifetime than just a youthful complexion and flawless style.
Is Kym Marsh really 40? The former Hear'Say singer - who rose to fame back in 2000 on reality series Popstars - is now best known for her role as Coronation Street's Michelle Connor. It feels like she's been around forever, far more than 16 years.
Emma Bunton is the youngest of the Spice Girls, and the last one to turn 40. The bubbly blonde turned the milestone age in January this year, but looks every inch the Baby Spice we know and love from the 1990s.
For those who grew up watching 1990s TV, it will be a difficult pill to swallow to learn that Melissa Joan Hart is another 40-year-old star. The former Clarissa Explains It All and Sabrina The Teenage Witch actress is married with three children, but doesn't look a day past her late 20s.
Colin Farrell is another "you won't believe he's 40´´ celebrity. The ruggedly handsome and permanently bearded acting hunk celebrated his birthday on May 31.
It's easy to look at 40-year-old Reese Witherspoon and still see her as the keen student in her iconic role from 1999 movie Election. Is it possible she has found the fountain of youth?
Red-haired and perennially angel-faced, Isla Fisher celebrated her 40th birthday on February 3 this year. We'll have what she's having please.
British acting stalwart Anna Friel is another new 40-year-old, having marked her birthday on July 12. Having become a national sensation back in the 1990s thanks to her role in soap Brookside, she has now gone on to achieve global fame thanks to her US TV hit series Pushing Daisies.