Majel Barrett Roddenberry (23 February 1932 – 18 December 2008; age 76) was a recurring actress in the Star Trek franchise and was the wife of Star Trek creator Gene Roddenberry. Her most frequent portrayal in Star Trek, besides the computer, was that of Christine Chapel on Star Trek: The Original Series, Star Trek: The Animated Series, and in two of the films. She also voiced M’Ress and several other characters on The Animated Series and later played Betazoid Ambassador Lwaxana Troi on Star Trek: The Next Generation and Star Trek: Deep Space Nine. Her first filmed appearance was in the original Star Trek pilot episode “The Cage” as Number One in 1964. link
Jeffrey Alan Combs (born 9 September 1954; age 70) is an actor who has the distinction of portraying nine different characters on four Star Trek television series link
Vaughn Dale Armstrong, Jr. (born 7 July 1950; age 74) is a veteran Star Trek actor who is noted for portraying twelve separate characters in twenty-eight episodes over four separate series. link
More than just an actress. Majel is the one who encouraged Gene to pitch Star Trek to producers after suggesting some changes to his original idea. She’s one of the reasons the show existed at all.
Her last role in Star Trek was the voice of the computer in the 2009 reboot movie. Unfortunately, she died before it was released.
She also was the computer voice in the last two episodes of PIC thanks to archive audio.