If you look at the name tape on his uniform, you’ll see that he’s Col. Lucas. He picked out the name himself. 
Ratzenberger was also in Clint Eastwood’s Firefox. He was the USN chief responsible for refueling the airplane on the icecap. He certainly got around before landing his role on “Cheers!”
Reading about “Combat!” made me think of Ted Knight as a German NCO, well before he became famous as Ted Baxter on “MTM.” He also played a Nazi in the 1962 film Hitler, starring Richard Basehart.
I love watching old shows like “The Untouchables” and “Perry Mason” and seeing actors who later became famous on their own series playing all kinds of bit parts (e.g., Jack Lord and Neil Hamilton).
Richard Dreyfus also had a bit part in The Graduate, some time before he became famous. He was the lodger who asked Norman Fell “You want me to call the cops? I’ll call the cops!”
Sammy Davis, Jr., Don Ho, Werner Klemperer, Art Linkletter, Edward G Robinson, Jerry Lewis and others on Batman.
A Guide for the Married Man was a mid-60s movie, purporting to be a how-to guide for committing adultery. Much of the movie was brief vignettes, as the Robert Morse character explained various techniques and pitfalls to the Walter Matthau character. These vignettes starred about a hundred reasonably well-known Hollywood celebs, all of whom were credited as “Technical Consultant”.
The idea being, of course, that adultery was so common in Hollywood that these people were all experts in the subject.
And, in one of the very first scenes, you can see an uncredited Angelique Pettyjohn happily jiggling down the street. Not a “star” in any sense of the word, but a year or so later she would forever be unforgettable as “Star Trek’s” Shahna, from “The Gamesters of Triskelion.”
No one seems to have mentioned Colonel Sanders in Hell’s Bloody Devils yet. That was the first one I thought of.
My favorites have to be the ones from Police Squad.
Dick Clark
Tommy Lasorda
Dr.Joyce Brothers
Lorne Greene
Robert Goulet
William Shatner
Florence Henderson
William Conrad - this one’s in French!
Since this is a bit of a zombie thread, how about Chris Martin from Coldplay in Shaun of the Dead.
:eek:
The Magnificent Seven will never be the same again. 
Edit: I know this is a zombie.
We had a newer thread on this subject a couple of months ago, where I mentioned my surprise at seeing Stephen Fry make a brief appearance as a computer nerd/Secret Service gadgetmaster in a 2006 teen adventure flick called Alex Rider: Operation Stormbreaker.
Keeping the zombie cameo theme running…
How about Bill Murray in Zombieland?
[QUOTE=io9]
The giant cameo that people saw inside Zombieland this weekend was none other than Bill Murray himself, pretending to be a zombie, so he could remain safe inside his Hollywood mansion.
[/QUOTE]
More a character cameo than an actor cameo, but the replacement juror in Runaway Jury is a petite, pale brunette named Lydia Deets, as in Lydia Deets in Beetlejuice.
Speaking of strange cameos, how about Tom Cruise, Gwyneth Paltrow, Kevin Spacey, Danny DeVito, John Travolta, Steven Spielberg, and the Osbournes in “Austin Powers in Goldmember”?
Here’s a somewhat strange cameo in “Rosemary’s Baby” (1968). At about 4:09 of this video, you can see (producer) William Castle’s cameo as a person waiting to use the phone. Nothing unusual about producers and directors giving themselvs cameos, but what makes this one a little weird is. . .
They did a bait and switch. I’ve cued the video at 3:28. That’s the back of Ralph Bellamy’s head that you first see, as the person waiting to use the phone. He has a major role in the film as Dr. Sapirstein. He then walks off to the left, and then Castle walks onscreen–but with his back to us, as Bellamy did previously, and wearing the same kind of coat.
I know I’m responding to a zombie post, but Larroquette appeared in STIII before he became famous as Dan Fielding in Night Court. Prior to that, his most prominent role was that of Captain Stillman in Stripes. This would fall more into a “before they were famous” thread.
And while we’re slumming along in zombieland, I thought I’d throw out this: I am certain John Ratzenberger has a cameo in an early episode of Moonlighting, “Devil in a Blue Dress” - the bizarre Whoopi Goldberg episode where they end by running off into the studio lot. Someone gets a ride with a cowboy on a horse, and I have watched the sequence closely, listened to the voice carefully, and am certain the cowboy is John Ratzenberger. However, the role is credited to an actor with exactly that one credit - Roy something or other.
The SDMB is one of the few places where “famous on their own series” and Neil Hamilton are mentioned in the same sentence. Before acting Hamilton was a shirt model, the nineteen-teens being AFTER the heyday of the celluloid collar models a Romney campaigner likened the Mittster to. And a cover boy!
“Hmm, Yul Brynner in drag. Could look worse. Wait, that’s ROMAN POLANSKI!” I see that The Magic Christian is a cameo extravaganza. I may have to see it.
Dunno if I agree with your interpretation of the director’s views on Ratzenberger, since he (Richard Attenborough) directed him 5 years earlier in “A Bridge Too Far” where the future Mr. Clavin did use his own speaking voice.
And yeah I know this a 3 year old comment.
Plus, at the end during the prison “Jailhouse Rock” scene, guitarist Joe Walsh is the shaggy blonde prisoner first seen banging his cup and then jumping up onto the table to dance. By that time he was well known for the James Gang and Eagles.