Bradley Walsh and Tosin Cole are to leave Doctor Who.
Revolution Of The Daleks, a special episode which will air on New Year’s Day, will be the actors’ last episode.
Alongside Mandip Gill, who is remaining part of the programme’s cast, the pair formed part of a trio of companions for the Doctor.
They joined the programme in 2017 as Jodie Whittaker took over the lead role and the actors starred in the 11th and 12th series of the BBC sci-fi show.
Cole, 28, who plays Ryan, said his final scene was “emotional”.
“I was looking forward to having a rest though,” he added.
When asked what he would miss about the programme, he said: “There are too many things to list here, but it has to be the team on the screen and behind it as well as the amazing fans.
“It’s been an honour to work on such a cultural institution with fans across the world.
“The people like me on the screen come and go, but it’s the people behind the scenes and the fans that will always be there keeping the Doctor Who world alive and exciting.”
Walsh described his and Cole’s last episode as “very, very dramatic”.
“It is quite sad and poignant is the word. You can expect a lot of poignancy from the episode.”
He said working “in Wales with everyone on the crew” was his highlight of being in the programme.
“I have absolutely loved it, loved it,” Walsh added.
He said Wales “has become like a second home to me” and that he is pleased to have starred “in something so iconic and groundbreaking with the advent of having a female Doctor”.
Walsh, 60, said he is “in constant contact” with people who worked on the programme, adding: “I miss them all. I was texting the location guys across the airwaves.
“Happy days. Fantastic memories. Our times abroad, when we were in Spain, South Africa, I just loved it.”
Revolution Of The Daleks will see John Barrowman reprise his role as Captain Jack Harkness, while Chris Noth will also return as Jack Robertson.
Revolution Of The Daleks will air on BBC One on New Year’s Day.