Tom Baker - former Doctor Who - has led tributes to Nicholas Courtney, known for his role as The Brigadier in the sci-fi drama, following the actor's death at the age of 81.
Courtney starred in more than 100 Doctor Who episodes as Brigadier Alistair Lethbridge-Stewart and played opposite five Doctors.
He died on Tuesday evening after a lengthy battle with cancer. He had also suffered a stroke in recent years, which had affected his ability to reprise the role.
Baker - who played opposite him as the fourth incarnation of The Doctor - said: "We shall miss him terribly. Of all the characters in Doctor Who there is no doubt that he was the most loved by the fans for his wonderful portrayal of the rather pompous Brigadier."
The actor died in a north London hospice with his wife Karen at his side.
The Brigadier was a key figure in the Time Lord's adventures during Jon Pertwee's run as The Doctor, but popped up regularly opposite other stars including Baker. As the chief of UNIT, who first appeared in the late 1960s, he led efforts to protect the earth against attacks.
His last official appearance in the show was in 1989, the year the series was cancelled. It was revived to a new level of popularity in 2005.
Michael McManus, who worked with him on his second memoir, confirmed the actor's death.
The Egypt-born star went to drama school after his national service and went into repertory theatre. In the 1960s he picked up a string of TV roles including appearances in The Saint, The Champions and The Avengers.
Others who paid tribute included actor and Doctor Who writer Mark Gatiss who said he was "desperately sad" to hear of the death, impressionist and Doctor Who buff Jon Culshaw, who called Courtney "a brilliant actor and warm, charming man" and film director Edgar Wright who said "he was a true gent."