Remember when David Tennant and Michael Sheen – sorry, Michael Sheen and David Tennant – made a little comedy series in the summer to keep us entertained during lockdown? Well, here we are six months later and lockdown is effectively upon us again. The novelty of staying at home baking sourdough has definitely worn off, but the novelty of two esteemed actors sending themselves up just about holds.

Staged (BBC One) is based on the real-life friendship between the pair. Do they banter like this in real life? Who knows. But if series one wasn’t meta enough for you, series two kicked off with them appearing on a pretend show – Romesh Ranganathan’s Six Months in Lockdown, “a celebration of the wonderful things that have got us through this period” – to discuss Staged, their real show. Ranganathan assured them that they were very funny. This was all self-indulgent and smug, but they were deliberately being self-indulgent and smug so I guess that makes it not self-indulgent and smug? Best not to give this too much thought.

Anyway, the joy of this episode (apart from the 15 minute running time, which should be applied to plenty more programmes) wasn’t in either of the leads but in a cameo appearance by Michael Palin, deftly making fun of his reputation as the nicest man in television. Palin was a fellow guest on Ranganathan’s show, and during recording he was his charming, good-natured self.

Then Ranganathan popped to the loo and filming was paused, and Palin revealed his true colours: “I didn’t really like Staged. I don’t really like improvisation – all these people rolling the comedy dice and hoping something sticks. We worked hard in our day.” And of Monty Python: “They still talk about us now. But they won’t talk about you, because you’re not funny.” Ouch.

Triumph turned to disaster as Staged was snapped up for the US market, only for the stars’ US agent (Whoopi Goldberg) to deliver the bad news that the roles were being recast for the American market. Colin Firth and Hugh Grant were being mooted for the roles. “They’re not American! They’re more British than we are!” spluttered Sheen. Ah yes, said Goldberg, but they were more famous and more believable as friends.

“I’m funny. Colin Firth is not funny,” Sheen insisted. Which was funny, although Staged is at its best when the duo are being funny, rather than debating whether or not they’re funny.