British actor Richard Griffiths, best known for his roles in Harry Potter and the cult film "Withnail & I", has died aged 65, his agent said on Friday.
The portly star of stage and screen, one of Britain's best loved character actors, died on Thursday from complications following heart surgery, his agent Simon Beresford said.
Griffiths will be forever remembered by fans of cult classic "Withnail & I" as the amorous Uncle Monty, although he reached his biggest audience as Uncle Vernon Dursley in the Harry Potter films.
Daniel Radcliffe, who played the boy wizard in the blockbuster Potter series, led the tributes to Griffiths who he said had offered him "encouragement, tutelage and humour".
"Richard was by my side during two of the most important moments of my career," Radcliffe said in a statement.
The first was in August 2000, when Radcliffe was filming his first ever shot as Harry. "I was nervous and he made me feel at ease," the actor recalled.
"Seven years later, we embarked on Equus together. It was my first time doing a play but, terrified as I was, his encouragement, tutelage and humour made it a joy," Radcliffe said.
"In fact, any room he walked into was made twice as funny and twice as clever just by his presence. I am proud to say I knew him."
Beresford said the late star "brightened my days and enriched the life of anyone he came into contact with".
"Richard gave acting a good name. He was a remarkable man and one of our greatest and best-loved actors. He will be greatly missed," he said in a statement.
Nicholas Hytner, who directed Griffiths in one of his biggest hits in Britain, The History Boys, said he was "the life of every party".
Griffiths won several awards for his theatre role as an inspirational teacher in The History Boys in London and New York, and later won a Bafta nomination for his role in the film version.
"His performance in The History Boys was quite overwhelming: a masterpiece of wit, delicacy, mischief and desolation, often simultaneously," said Hytner, the director of the National Theatre in London.
"But that was just one small part of a career that spanned Shakespeare, cutting-edge new plays and major work in film and television."
The actor, from Yorkshire in northern England, was awarded an OBE for services to drama in 2007.