Robert De Niro, Jim Carrey and more mourn Jerry Lewis on social media

Aug. 21 (UPI) -- A number of celebrities, including Robert De Niro, Jim Carrey, Whoopi Goldberg, have paid their respects to Jerry Lewis on social media following the comedian's death.

Lewis died Sunday of natural causes at the age of 91. The screen legend was said to have been in poor health for many years, undergoing open-heart surgery, battling prostate cancer and dealing with pulmonary fibrosis.

Lewis starred in classic comedy films such as The Ladies Man, The Errand Boy, Cinderfella, The Nutty Professor and The Disorderly Orderly.

"Jerry was a pioneer in comedy and film. And he was a friend. I was fortunate to have seen him a few times over the past couple of years. Even at 91, he didn't miss a beat...Or a punchline. You'll be missed," De Niro said in a statement shared by senior entertainment editor for The Daily Beast Marlow Stern on Twitter.

"That fool was no dummy. Jerry Lewis was an undeniable genius an unfathomable blessing, comedy's absolute! I am because he was!" tweeted Carrey alongside a photo of a young Lewis.

"Jerry Lewis passed today,millions around the world loved him,millions of kids he helped w/his telethons. R.I.P. &condolences 2 his family," added Goldberg.

"Condolences to the family of Jerry Lewis. The world is a lot less funnier today," Shatner shared on Twitter.

"We lost one of the great ones today...possibly the greatest. Jerry Lewis was one of my comedy heroes & was a gigantic inspiration to me. I am so grateful to have shared some valuable time with him. RIP #JerryLewis," Will & Grace star Sean Hayes wrote on Instagram alongside a photo of himself and Lewis.