From an Anonymous Blogway Baby contributor. All I have to say is WOW...where did you find all of these? Although Cocoon seems to have picked off about half the group:

Ricardo Montalban
Broadway: Jamaica (Off-Broadway The Fantastiks)
SF Movie: Star Trek: The Wrath of Khan

Fred MacMurray
Broadway: Three's a Crowd
SF Movie: Absent-minded Professor (hmmm...)

Whoopi Goldberg
Broadway: A Funny Thing Happened on the Way to the Forum
SF Movie: Star Trek The Next Generation (TV Series), Star Trek Generations

Hank Azaria
Broadway: Spamalot
SF Movie: Godzilla (1998)

Gwen Verdon
Broadway: Sweet Charity
SF Movie: Cocoon

Jack Gilford
Broadway: A Funny Thing Happened on the Way to the Forum
SF Movie: Cocoon

Don Ameche
Broadway: Silk Stockings
SF Movie: Cocoon

Elaine Stritch
Broadway: Company (etc. etc.)
SF Movie: Cocoon II

Conrad John Schuck
Broadway: Annie
SF Movie: Star Trek IV: The Voyage Home

Carrie Fisher
Broadway: Irene
SF Movie: Star Wars Trilogy

Billy Dee Williams
Broadway: Hallelujah, Baby!
SF Movie: Star Wars V & VI

Adrienne Barbeau
Broadway: Grease
SF Movie: Swamp Thing

Paul Lynde
Broadway: Bye, Bye Birdie
SF Movie: Son of Flubber (Hmmm again...are these Disney flicks really SF?)

Diane Keaton
Broadway: Hair
SF Movie: Sleeper