Richard Griffiths, the British actor who famously played Uncle Vernon Dursley in the Harry Potter series, has died at age 65.

Richard Griffiths' death was announced by his agent Simon Beresford on Friday, March 29. Griffiths died on Thursday of complications following heart surgery at University Hospital in Coventry, central England, according to the Associated Press.

Beresford said that Griffiths was "a remarkable man and one of our greatest and best-loved actors."

In addition to appearing in the Harry Potter films as the wizard's Muggle guardian, Griffiths has starred in dozens of movies and television shows. He was most famous for playing flamboyant Uncle Monty in the 1980's cult classic Withnail and I.

Griffiths was one of Britain's leading theater actors. He created memorable roles, including the charismatic teacher named Hector in "The History Boys." Griffiths took the part to Broadway and won a Tony Award. He reprised the role in the film adaptation.

National Theatre artistic director Nicholas Hytner, director of "The History Boys," called Griffiths' performance in the play "a masterpiece of wit, delicacy, mischief and desolation, often simultaneously."

Richard Griffiths also played poet W.H. Auden in "The Habit of Art." The AP stated that Griffiths' portrayal strikingly resembled the poet, although they looked nothing alike.

Griffiths was known for his sense of humor, interesting theatrical anecdotes and bursts of temper. He was also famous for his outbursts shaming audience members whose cell phones went off during plays. If he heard a ring in the middle of a performance, he would stop the show and order the offending person to leave.

Griffiths' last major role was in a West End production of Neil Simon's "The Sunshine Boys" opposite Danny DeVito last year.

In 2007, Griffiths reunited with Daniel Radcliffe, star of Harry Potter, for the play Equus.

Radcliffe said on Friday in a statement, "Richard was by my side during two of the most important moments of my career."

"In August 2000, before official production had even begun on Potter, we filmed a shot outside the Dursleys', which was my first ever shot as Harry. I was nervous and he made me feel at ease."

"Seven years later, we embarked on 'Equus' together. It was my first time doing a ply but, terrified as I was, his encouragement, tutelage and humor made it a joy. In fact, any room he walked into was made twice as funny and twice as clever just by his presence."

Radcliffe said, "I was proud to say I knew him."

Richard Griffiths is survived by his wife, Heather Gibson.