Celebrated actor, director, producer and activist Rob Reiner, whose work shaped American television and cinema for decades, has died at 78, according to Variety and TMZ. His death, alongside that of his wife, Michele Singer, 68, is under investigation by the Los Angeles Police Department after the couple was found in their home in Brentwood, California.

A dedicated political activist, Reiner was slated to speak on Tuesday, Dec. 16, in Palm Springs, Calif., about his career and his book  “A Fine Line Between Stupid and Clever: The Story of Spinal Tap.”

Reiner, born March 6, 1947, in the Bronx, New York, grew up in the entertainment business − his father was comedy legend Carl Reiner and his mother, Estelle, was an actress. He became famous in his own right for his portrayal of Michael “Meathead” Stivic on the groundbreaking sitcom “All in the Family,” winning two Emmy Awards as Archie Bunker’s son-in-law. 

Live updates: Rob Reiner, his wife killed in apparent homicide

Though he had dozens of acting credits to his name, he transitioned to directing and created beloved films including “This Is Spinal Tap,” “Stand by Me,” “The Princess Bride,” “Misery,” “A Few Good Men” and “When Harry Met Sally …” He cast his mother as an extra in the rom-com classic for a scene at a New York deli where Meg Ryan faked an orgasm. 

“First couple of times, she didn’t do it full out,” Reiner said of directing Ryan in the scene. “Finally, I sat across from Billy (Crystal). And I acted it for her. … And I’m pounding the table, ‘Yes! Yes! Yes!’ And I’m realizing I’m having an orgasm in front of my mother, you know? There’s my mother over there.” His mother’s line – “I’ll have what she’s having” – became one of the most famous lines in film.

Similarly, his mockumentary “This Is Spinal Tap” was a part of the cultural landscape (and earned a spot in the Library of Congress’ National Film Registry), with memorable songs like “Gimme Some Money.”

Reiner admitted that was the very reason “Spinal Tap II: The End Continues” came to be: “We never got any money from the first movie, really,” Reiner said in an interview with USA TODAY earlier this year about his three stars, Christopher Guest, Michael McKean and Harry Shearer. “Lots of people had the rights, and the four us had 10% each, and while it’s going to sound crazy, we only got like 82 cents apiece over the years, despite all the DVD and foreign sales. Call it creative accounting on steroids. So Harry said, ‘I’m going to sue to get the rights back,’ and though it took him years, he got it done.”

The sequel was largely improvised. “The fun thing for me was falling back with old friends,” he said. “You just start doing your thing with each other, Chris used to call it ‘schneedeling,’ and right away, we were schneedeling as if no time has gone by. You can’t beat that.”