Portrayed/appeared in same film

And W(inifred) E(llen) B(arabara) Dubois.

Defintely not Alfie, who died in '59, I think. Didn’t see any recognizable names in the credit list, so if it’s true, whoever it is is probably uncredited.

In a movieabout Spike Milligan’s experiences as a WW2 conscript, Spike played his own father.

Special mention must also go to BAADASSSSS! (2003), about the filming of Sweet Sweetback’s Baadasssss Song (1971). Melvin Van Peebles is played by his son Mario. Mario also appeared in the original movie, as a younger version of his father’s character, so a young Mario appears in BAADASSSSS! as well.

For something a little less complex than this, Pee Wee Herman has a cameo in the film-within-a-film in Pee-wee’s Big Adventure.

This is hard to believe…the youngest rascal would have been at least 60 when this movie was released (1994). Grandparent, maybe, but parent???

There’s a third one - Howard Devoto, played by Martin Hancock. The real Howard Devoto plays a toilet cleaner.

A quick check on the film’s Wikipedia entry has a fourth - Vini Reilly of the Durutti Column, played by Raymond Waring in the film, has a cameo somewhere in the film.

In Searching For Bobby Fischer, Ben Kingsley plays Bruce Pandolfini, and the real Pandolfini has a line calling a boy a “young Fischer”.

Hmm, now that you mention it, I think you’re right. None of the parents in the movie seemed old enough to be the kids from the old series. It’s been a long time since I’ve seen the movie, so it may have been a grantparent or some other older character.

Stephen King played Jody Verrill (and his son Joe had a cameo) in the film adaption of five of his short stories Creepshow

In the Brady Bunch Movie (or was it the sequel?), Florence Henderson (who played Carol in the TV show) played Carol’s mother, and Ann B. Davis (who played Alice in the show) played a truck driver.

There was a 1980’s made-for-TV movie about Ryan White, the teenager with AIDS who would later die. White had a small bit part in that movie.

You missed a couple! Barry (Greg) Williams was the agent who wouldn’t sign “Johnny Bravo.” Christopher (Peter) Knight was the blurry guy who told Bobby’s bully to get lost. Mike (Bobby) Lookinland was a cop. Susan Olsen apparently had her scene as a reporter cut, but I could swear that was her comforting Marsha’s lesbian pal near the end of the movie.

In this same vein, in the movie “His Girl Friday,” Cary Grant describes Rosalind Russell’s fiance as looking like, “that actor, Ralph Bellamy.” Of course, the fiance is played by Ralph Bellamy.

Wow, and I thought he was already dead. The pictures of him on imdb look a lot better than the one they showed at the end of the film.

Well, I’ll be a monkey’s bare-assed uncle. I never knew so many cast members from the show were in the movie.

Continuing in the vein of not really what the OP wanted…

For some reason tonight I remembered a horrible Bob Hope special from the '70s (as opposed to all the good Bob Hope specials from the '70s) in which a bunch of comedians were murdered at a party. The guest list included what was left of Groucho Marx. He was barely capable of speaking at the time, much less moving, so his presence was augmented by Billy Barty running around him in Groucho drag. At one point, George Burns asks, “Who’s that?” and Groucho replies “Me as a kid.”

This debacle was titled “Joys,” which was funny because “Jaws” was a popular movie of the time about a shark that terrorized a resort town, and this was a TV special featuring comedians at a party at Bob Hope’s… meh.

BUMP!

In the Longest Day, Richard Todd played the part of Major Terence Howard, and he meets up with another officer later, the officer being; Richard Todd!

King has a cameo in damn near every adaptation of his work.

The real Pappy Boyington had a cameo appearance as a visiting general in an episode of Baa, Baa, Black Sheep, playing against Robert Conrad as, of course, Boyington.

The judge in Anatomy of a Murder was played by real-life lawyer Joseph N. Welch, of the Army-McCarthy hearings. For some reason, judges seem to be popular roles for these sort of cameos. Perhaps because there usually isn’t a whole lot of acting required.

Steve McQueen played Ralph “Papa” Thorson in The Hunter, in which Ralph Thorson played a bartender.

Aaaaaaand Mark E. Smith plays a doorman. Smith was supposed to be played by Sam Riley but the scene was cut out. It does appear on the DVD, though.

The scene with Howard Devoto may be my favorite in the whole movie: “I definitely don’t remember this happening.”

Jim Morrison’s real-life Pagan “wife” Patricia Kennealy plays the Priestess that handfasts Jim & the movie version of her, played by Kathleen Quinlan.