Losing heart: Has Miranda Hart sold out with new exercise video?

Miranda Hart will hobble through her Strictly Come Dancing set for Comic Relief (PA)

Miranda is releasing a fitness DVD. I know. Bear with. Miranda Hart’s Maracattack will feature routines from Hart and fitness expert Amelia Watts – cardio sessions, core strength exercises etc. - set to a feelgood soundtrack of Kylie and Take That and interspersed with sketches starring Miranda’s mum, Stevie and Gary.

“Fitness should be fun”, said Hart(right). “It’s about playing, not ‘working out’ and play helps your body, but also frees your mind. The DVD involves maracas, classic pop tunes, and is as much fun as a riotous camp, cheesy disco.” It will be released by BBC Worldwide next month, in time to fill Christmas stockings across the land.

I have been struggling with this a bit, and not just because I don’t own any maracas (a merchandise opportunity here, BBC Worldwide). On the one hand, Hart is known and loved for her physical comedy so perhaps a fitness DVD makes sense. It might even be inspiring. If clumsy, pratfalling Miranda can follow a 5-minute, high-intensity cardio workout, anyone can.

On the other hand, it looks dangerously like a sell-out. And of all the sell-outs, a stand-up sell-out is the worst. There is nothing more disheartening than the sight of a favourite comedian taking a break from sticking it to the man to hawk cider, cheap hotels or car insurance. Or exercise DVDs. Or anything, really. Comedy and commerce are an unhappy mix.

Perhaps this is unfair. It is not easy being a fictional national treasure. Create a much-loved comedy character and you are fated to be remembered as him or her for all eternity - trapped in a purgatory of catchphrases, fancy dress tributes and Christmas specials. The people always want more. The traditional options are to keep doing what you’re doing until you are as old as Compo and co. or to burn out gloriously in 12 episodes like Basil Fawlty.

Or, to diversify. Alan Partridge has managed it. Steve Coogan exhumed his best character first with a low-key web series, Mid Morning Matters, then with a couple of one-off Sky specials and finally a movie outing in Alpha Papa this summer. And now, a decade after the last episode of The Office aired, David Brent has returned. Like Partridge, he was first reborn online with a series of spoof guitar tutorials on YouTube. Offers to play Wembley apparently followed, and so this week Brent took to the Bloomsbury Theatre stage for his first work-in-progress gig, singing cringe classics such as “Slough”, “Free Love” and “Equality Street” to a delighted crowd. The sight of him walking onto the stage wearing an earring – “Fashion, innit?” – was enough to provoke waves of laughter. He didn’t do the robot dance. He didn’t need to. This was a new direction for a proven comedy hero and it worked.

Hart has also created a character so beloved that she could dictate the phone book and make a room howl. So it is to her credit that she is trying something new. Brent has taken up air guitar, Miranda has gone for maracas. Call it money-spinning, call it diversifying – as long as it’s funny, they can carry on.

New slant on TV panel show

Just when it seemed that every possible TV panel show had been commissioned, here comes a new one, from Fox. Its angle? It takes place at an angle. “Slide Show” will be presented by Steve Carell (above) and will pit teams of celebrities and comedians against one another in song, dance and sketch on a set that is tilted at a 22.5 degree angle. The show is based on the French format Vendredi, tout est permis which, from YouTube clips looks like a hyperactive Whose Line is it Anyway? Next up, Arm Wrestling with Chas and Dave and Monkey Tennis, possibly.