Not sad at all…
Speaking of John De Lance, anyone remember him as Eugine Bradford?
(Also the skeevy gynecologist in The Hand That Rocks the Cradle.)
Laurel (Yeoman Colt) Goodwin was in, “Girls, Girls, Girls,” an Elvis movie.
Nimoy’s in an episode of Get Smart.
Shatner is in an episode of The Outer Limits.
“Crewman Green” from the Salt Monster episode is a friend of
“Benjy Carver” a.k.a. “Blue Boy” in what is arguably the best episode of Dragnet 1967,
“The LSD Story.”
So many others…
He also played the lead in Ensign Pulver the bad sequel to Mister Roberts.
In an episode of Roswell Jonathan Frakes played an obnoxious actor named Jonathan Frakes who was a guest at an alien convention.
Also a pilot in *Die Hard *2, who was tricked into crashing his plane.
When I watched The Outer Limits episode “Controlled Experiment,” I couldn’t figure out who this familiar looking woman was.
Grace Lee Whitney – Yeoman Janice Rand
Alice (Borg Queen, “First Contact”) Krige was very naked in the movie, “Ghost Story.”
I looked her up on IMDb a while ago and was surprised at how many things she’d been in that I’d never noticed was the same actress. She’s in the classic Outer Limits episode Demon With a Glass Hand.
She was one of Becker’s ex-wives. I’m not going to count Terry Farrell since she went to Becker directly from DS9 and was one of the leads in the series.
Frakes was in an episode of the New Twilight Zone, where a secretary gets transported to a world where they’re treated like royalty. He hits on het at a bar and when he finds out she’s a secretary he curses himself for blowing a chance with her.
So many to choose from! For starters…
Arlene Martel was in “What You Need,” in one of the first episodes of Twilight Zone. She was also “Tiger” of the French Resistance on Hogan’s Heroes.
Sabrina Scharf (“Miramanee”) was part of a Gestapo “interrogation team” :o on Hogan’s Heroes.
Jimmy Doohan was the father of Morgan Brittany (then known as Suzanne Caputo) in “Valley of the Shadow” on Twilight Zone. He was also an advisor to the US President in the pilot of Voyage to the Bottom of the Sea.
Both Leonard Nimoy and Walter Koenig played GIs on Combat!
Both Diana Muldaur and Joanne Linville (Miranda Jones (among other roles) and the Romulan Commander, respectively) were on the original Hawaii Five-O, the former as McGarrett’s old girlfriend and the latter as a faith healer.
Joanne was also in “The Passersby,” one of the first episodes of Twilight Zone. She was also the whiny alcoholic wife of Jackie Cooper, the murderer in an episode of Columbo.
William Windom (“Commodore Decker”) was in “Five Characters in Search of an Exit” on Twilight Zone. Also The Farmer’s Daughter and My World—and Welcome to It.
Sherry Jackson (“Andrea the Android”) played opposite Frank Gorshin (“Commissioner Beale”) in a Riddler episode of Batman. Sherry was also in “The Last Rites of Jeff Myrtlebank” on Twilight Zone.
Majel Barrett (“Nurse Chapel”) was a waitress in an episode of the original The Untouchables. Stanley Adams (“Cyrano Jones”) was also in The Untouchables, as a wanna-be gangster.
Grace Lee Whitney (“Yeoman Rand”) was a member of the all-girl band in Some Like It Hot.
Lloyd Haynes (“Lt Alden” in the second pilot) moved on to play teacher Pete Dixon on Room 222. (According to Wiki, he died of lung cancer in 1986 at the age of 52! 
)
Here’s a really obscure one for you: Bruce Watson (“Crewman Green” in “The Man Trap”) was a gunslinger in an episode of the CBS comedy western Pistols ‘n’ Petticoats (1966–67), the pilot I think. This series starred '40s babe Ann Sheridan shortly before she also died of lung cancer.
DeForest Kelley played a bad guy in the pilot episode of The Cowboys, a spin-off of the John Wayne movie.
Just saw James Gregory (“Dr Adams”) in “Where is Everybody?” on Twilight Zone. Also from “Dagger of the Mind”: Morgan Woodward (“Dr van Gelder”) was one of JR’s nemesises on Dallas; Marianna Hill (“Dr Noel”) was the town floozy in Clint Eastwood’s High Plains Drifter.
Billy Curtis, one of the ambassadors in “Journey to Babel,” was the town dwarf in High Plains Drifter.
Sharon Acker (“Odonna” in “Mark of Gideon”) was “Edwina” in an episode of It Takes a Thief (Ed, do you think you can take your glasses off, let your hair down, and come on as sexy? :dubious: ) Teri Garr (“Roberta Lincoln” in “Assignment: Earth”) was also in It Takes a Thief as a cute little airline stewardess.
George Takei was a Red Chinese agent in an episode of It Takes a Thief set in Africa.
Lots of others. Ken Lynch, Frank Overton, Madlyn Rhue, Jill Ireland, Susan Howard, Michael Ansara, John Colicos, William Campbell. And so on, and so on.
Let’s not forget Bill Shatner in Incubus, the pilot for Alexander the Great, and the short-lived Barbary Coast. He was also in The Andersonville Trials, which was excellent!
And Majel Barrett was in the failed pilot Genesis II as one of the heads of the post-apocalypse organization Pax.
Mariette Hartley (“Zarabeth” in “All Our Yesterdays”) was also in Genesis II as a mutant with two (count 'em, two!) navels. :o
Malachi Throne (“Commodore Mendez” in “The Menagerie”) was in both ***Batman *** (as “False Face”) and It Takes a Thief (as “Noah Bain”).
I remember seeing Liam Sullivan (“Parmen” in “Plato’s Stepchildren”) as a high-society type in an episode of Family Affair.
Susan Howard (“Mara, Kang’s wife”) was Mrs Ray Krebs on Dallas.
Barbara Bouchet (“Kolinda” in “By Any Other Name”) was in the original James Bond spoof Casino Royale.
Angelique Pettyjohn (“Shahna” in “The Gamesters of Triskelion”) was “Master of Disguise” Charlie Watkins on Get Smart.
One day with nothing to do, I plopped myself in front of the TV and watched some movie starring Leonard Nimoy as a Navy captain. He commanded a submarine and there was some question about his competence (he may have been drugged or otherwise incapacitated at some point), there were spies and codes and it seemed kind of odd to see Nimoy barking orders… very much unlike Spock.
Assault on the Wayne is very much a TV movie, but not too bad of one and it seemed to have similarities to Star Trek.