Richard Lewis, the cherished stand-up comedian and a prominent figure in "Curb Your Enthusiasm," passed away, as announced by his publicist.

At the age of 76, Lewis succumbed to a heart attack at his Los Angeles residence on Tuesday night, as confirmed by his publicist, Jeff Abraham.

In April, the actor disclosed that he had been grappling with Parkinson’s disease.

Joyce Lapinsky, Lewis’ wife, expressed her gratitude "for all the love, friendship, and support" and requested privacy during this period, as stated in Abraham's announcement.

Lewis is playing a co-starring role in the concluding season of Larry David’s “Curb Your Enthusiasm” on HBO.

On Wednesday, David expressed his grief over the passing of his lifelong friend.

"Richard and I were born three days apart in the same hospital, and for most of my life, he’s been like a brother to me. He had that rare combination of being the funniest person and also the sweetest," David said in a statement. "But today he made me sob, and for that, I'll never forgive him."

Lewis, born in Brooklyn and raised in Englewood, New Jersey, initially ventured into stand-up comedy in New York City in the early 1970s, alongside luminaries such as Richard Pryor, George Carlin, Andy Kaufman, Richard Belzer, and Elayne Boosler. He made a career of it when discovered by comedian David Brenner and, by the mid-'70s, had already graced "The Tonight Show Starring Johnny Carson."

Recognized as a dark comic, both literally and figuratively, Lewis was known for his all-black attire and frequently delivered self-loathing sets about his neuroses and addictions.

Lewis made his TV debut with "Diary of a Young Comic," a 90-minute movie that aired on NBC in 1979, replacing "Saturday Night Live." He rose to prominence with continued late-night appearances during the '80s and '90s.

In the '80s and '90s, he became a comedy rock star, starring in multiple stand-up specials on Showtime and HBO and making high-profile appearances on specials like the Comic Relief charitable fundraisers.

He starred alongside Jamie Lee Curtis in the sitcom "Anything but Love," which aired from 1988 to 1992, before featuring in a few short-lived sitcoms and movies throughout the late '80s and early '90s.

In an Instagram tribute, Curtis shared that Lewis "blew everyone else away" during his audition and mentioned that he was the reason she is sober. Curtis also noted Lewis's efforts to convince ABC and Disney to release another boxed set of episodes of their show.

In 2000, Lewis became a fixture on "Curb Your Enthusiasm," portraying a dramatized version of himself. The show, currently airing its claimed final season, features Lewis as his curmudgeonly character who often hits the golf course with Larry David. A season five storyline even featured David donating a kidney to Lewis.

David and Lewis go way back, having met for the first time at a summer camp when they were 12. Despite initially disliking each other as teens, they reconciled in the New York comedy scene as adults.

HBO, where "Curb" and many of Lewis' comedy specials aired, expressed being "heartbroken" over the comic’s death, praising his comedic brilliance, wit, and talent. They extended condolences to his family, friends, and fans.