The funnyman is famous for creating comedy characters Ali G, Borat, and Bruno - and between his alter-egos he's pulled pranks on stars including David Beckham, Eminem and Paula Abdul.
Cohen, who's married to actress Isla Fisher, keeps his personal life private, but there's no hiding his big day.
To mark Cohen's 40th, WENN has compiled 10 fascinating facts about the star. Happy birthday, Sacha!
- Born in London in 1971, Cohen was raised in a Jewish family and attended the U.K.'s prestigious University of Cambridge.
- Before finding fame as a funnyman, Cohen worked as a model and appeared in several fashion magazines.
- He shot to stardom in his native Britain in 2000 with cult series Da Ali G Show. His spoof character interviewed stars including soccer ace David Beckham and his wife Victoria, property mogul Donald Trump and astronaut Buzz Aldrin.
- Cohen is a big fan of professional wrestling and is friends with WWE wrestler John Cena.
- The funnyman is the proud owner of a Golden Globe - he won the 2007 Best Actor in a Musical or Comedy for his portrayal of Borat, a spoof Kazakhstani journalist.
- Cohen stunned viewers of the 2009 MTV Movie Awards by dressing as camp Austrian fashion journalist Bruno and falling from the roof of the venue into Eminem's lap. The rapper stormed off - but the stunt was later revealed as a prank.
- As Ali G, Cohen starred in Madonna's music video for hit single Music - he played a limousine driver in the promo. He also delivered the 2004 Class Day Address at Harvard University.
- Cohen wed his longterm partner Isla Fisher in a small private Jewish ceremony in Paris, France last year (10). The couple has two young daughters.
- The actor was the first choice to host the 2010 Academy Awards, but bosses thought he was too much of a "wild card" and handed the prestigious booking to Steve Martin and Alec Baldwin.
- Cohen will play late Queen frontman Freddie Mercury in a 2012 biopic, and the rocker's bandmate Brian May has given the actor his seal of approval.