Mitchell and Webb have collaborated on several projects throughout their career, including the BBC sketch shows Bruiser and That Mitchell and Webb Look.
Peep Show ran for nine seasons from 2003 to 2015, and focused on the uptight Mark Corrigan (Mitchell) and his self-obsessed slacker roommate Jeremy Usbourne (Webb).
The pair can next be seen starring in the second season of Back on Channel 4, which begins on 21 January at 10pm.
“The way we have it in mind – though the need to work may intervene, who knows, we may be pitching it in six months time – was not to do it when they were middle-aged but when they were old,” said Mitchell.