Red Dwarf's Robert Llewellyn asked fans of the show not to point out his wrinkles as the first image from the new series was released online.
Robert, Craig Charles, Chris Barrie and Danny John-Jules have reunited to play robot Kyten, spaceman Lister, hologram Rimmer and futuristic feline The Cat in a new series of Doug Naylor's sitcom Red Dwarf X, to air on comedy channel Dave later this year.
Robert tweeted: "Okay, steady with all the 'Kryten looks old' comments. The poor fella's been tapping away with a smeg hammer for 3 million + years."
Plot details of the new series are top secret, but Chris Barrie said: "I think we've done some of the best Red Dwarf scenes ever. Really looking forward to seeing what the fans think".
Red Dwarf, about a motley crew of space explorers, ran for eight series between 1989 and 1999 on BBC Two. The cast were then reunited for a three-part special in 2009 which also aired on Dave.
The new series will consist of six episodes, recorded in front of a studio audience this winter and expected to air in September.
Coronation Street's Craig has previously said he was delighted the soap gave him time off from playing cab driver Lloyd Mullaney on the cobbles, to reprise his role as the dread-locked, curry-loving, personal hygiene-lacking Dave Lister.
He said: "I'm just really glad they've let me do that because I wasn't sure they would at first, they've never done it for anybody else. But it'd have been a shame to have missed Red Dwarf - it'll have been 25 years since we started it. I can't believe it's been that long!"