Did the guy that plays joker in dark night die real life?

You're likely thinking of Heath Ledger, who played the Joker in "The Dark Knight". Sadly, he passed away in 2008 from an accidental overdose of prescription medications.

His death was a huge loss for the film industry and for fans worldwide. He was a talented and versatile actor and his performance as the Joker is considered one of the greatest villain portrayals in cinematic history.