The actor, who played Vernon Dursley in the Harry Potter movies and Uncle Monty in Withnail and I, died on Thursday (March 28) at the age of 65. Griffiths's agent has confirmed that the Tony, Olivier and Drama Desk award-winning star passed away from complications following heart surgery.
Read a selection of tributes to Griffiths from the entertainment world below:
"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 play but, terrified as I was, his encouragement, tutelage and humour made it a joy.
"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."
Richard E Grant
"My beloved 'Uncle Monty' Richard Griffiths died last night. Chin-chin, my dear friend... Here's the plan. Going to fire up a Camberwell firm young carrot in memory of my 'Uncle Monty' and raise a figurative glass of sherry to him."
Polaroid of my 'Uncle Monty' at full flowIn that Penrith cottage. twitter.com/RichardEGrant/…— Richard E. Grant (@RichardEGrant) March 29, 2013
'Mind the Oomska' as my 'Uncle Monty' was wont to say. Paul McGann, Richard Griff and Richard E up a hillside twitter.com/RichardEGrant/…— Richard E. Grant (@RichardEGrant) March 29, 2013
"Awoke to the awful news about Richard Griffiths. A mighty tree has fallen. Heart goes out to his family and loved ones. A brilliant, funny, principled man, and a true gent. Led the way on Withnail & I. Wore his great skill lightly and his great heart out. RIP."
"You got a great deal of support for having Richard about. He was lovely, he would always make time for his fans. That's what makes a great actor, it's about having a good persona."
"Desperately sad to hear the news of Richard Griffiths' passing. A superb, nuanced, naughty actor and an absolute gentleman."
"Really sad. Our mate and leader has moved on to the theatre in the sky. We will miss you so much Richard Griffiths. RIP you wonderful man x"
Sir Nicholas Hytner, director of the National Theatre
"Richard Griffiths wasn't only one of the most loved and recognisable British actors - he was also one of the very greatest. His performance in The History Boys was quite overwhelming: a masterpiece of wit, delicacy, mischief and desolation, often simultaneously.
"But that was just one small part of a career that spanned Shakespeare, cutting-edge new plays and major work in film and television.
"His currency as an actor was truth; as a colleague it was hilarity. His anecdotes were legendary. They were literally endless. They would go on for hours, apparently without destination, constantly side-splitting.
"The only way to stop them was to tell him you were walking away, though there were always others in the audience so, as far as I know, he never stopped. He was the life of every party."
Simon Beresford, Richard Griffiths's agent
"Richard brightened my days and enriched the life of anyone he came into contact with. On stage, he allowed us to share in our own humanity and constantly question our differences.
"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.
"Our thoughts and deepest sympathy go to his devoted wife Heather and his family at this sad time."
Richard Griffiths 1947-2013 - photo gallery: