Nana Visitor and Peter Mark Richman in the Matlock episode “The Other Woman.” Nana gave a very convincing performance as a woman with a dual personality.
Anthony Caruso as a mobster (again) in the M:I episode “Shape-Up.”
John Fiedler, Mr. Hengist in “Wolf in the Fold” in Peter Gunn, “The Deep End”. He played Mr. Oliver, who hired an ex alcoholic swimming instructor who was hypnotized to take a dink when Mrs. Oliver swam into the deep end of the pool and drowned.
“Take a dink?” 
James “Captain Styles” Sikking and Susan “Mara” Howard in the M:I episode “Committed.”
Joanne Linville, the Romulan commander in “The Enterprise Incident” in the Twilight Zone eopisode, “The Passerby”. It is about dead Confederate Soldiers. I thought she was Olivia DeHaviland until I Googled the episode. Perhaps she was made up to resemble DeHaviland.
She is still alive at 92.
BTW, Leonard Nimoy was in the Twilight Zone episode I watched before that, “The Quality of Mercy”.
Just watched the Thanksgiving classic Planes, Trains & Automobiles, which has five actors who also had ST appearances:
Outer Limits, Valley of the Shadow. James Doohan, without an accent and David Opatshu from “A Taste of Armageddon” playing the same sort of leader he did as Anan 7.
Outer Limits? Twilight Zone!
… And the little girl grew up to be Morgan Brittany.
And David Soul “Makora” in “The Apple”.
“4 D Man” Starred Robert Lansing (Gary Seven) and Lee Merriweather (Losira).
Good gad!
I knew this, but I managed to forget. I’ve known for years, but every time I see it, I say, “Good gad!” and try to wipe it out of memory.
David Soul was on Twilight Zone?
Perhaps I confuse him with Ernest Hemingway.
No, Star Trek.
“He believed he was watching an episode of Star Trek, the Original Series. When he saw David Soul, he knew he had re-entered…the Twilight Zone.”
Oh G-d, the eye glitter!
This, not “Spock’s Brain” is the worst episode.
Take a gander at the thread title.
We seem to have become discombobulated here.
My vote would be for the Friendly Lawyer. How the F did that happen?
George Takei in the Twilight Zone episode, “The Encounter”. Broadcast 1 May, 1964, racial overtones kept it from syndication. Reaired 1 Jan 2016.
Sarah Marshall, “Dr Wallace” in TOS’s “The Deadly Years,” as KAOS agent “Nicola” in the *** Get Smart*** episode “Hubert’s Unfinished Symphony.” Her voice was a dead giveaway.
SIDE NOTES:
Michael “Alexander” Dunn was KAOS’s “Mr Big” (but not in this episode).
Angelique “Shahna” Pettyjohn was CONTROL agent “Charlie Watkins,” a master of disguise (but not in this episode).
Victor French of Little House on the Prairie fame was “Agent 44,” who always turned up in the most unlikely places (e.g., mailboxes and bass violin cases). I never recognized him before because “44” had no beard.
“Agent 99” was really hot! 