David Walliams & Friend (BBC1, 9.30pm)

A ONE-OFF Christmas show with Joanna Lumley has produced this six-parter for David Walliams and his invited guest on location, in front of a live audience

The first friend to play an array of comedy characters alongside Walliams is stand-up and actor Jack Whitehall.

Walliams says of his co-star: "He's so, so funny. In fact, he is too funny. He needs to be stopped. He made me feel really old when he told me, 'I used to love watching Little Britain when I was at school.' [I said] 'I'm sorry, how old are you?' He's still in his 20s. It's absurd."

Whitehall has to dress up as a woman in one sketch, which Walliams writes with the Dawson brothers, and will also be straying into Benedict Cumberbatch and Martin Freeman's territory with a somewhat inappropriate take on Sherlock and Watson, and bringing us the world's worst dating show contestant.

"Often people think you're laughing all the time when you make this type of show, but often you're not, because it's hard work and there's a lot of concentration and stress. But this is probably the most fun I've had making a show.

"I was naughty to Jack. During filming one sketch I had to slap him quite hard a number of times. But he enjoyed it, I'm sure.

There's a recurring sketch involving Britain's cruellest reality show, Celebrity Slammer, in which Walliams finds himself locked up with the likes of The Chuckle Brothers and Bob Carolgees.

The friends include Sheridan Smith, Harry Enfield, who plays the Queen in Who Does One Think One Is?, Meera Syal, Miranda Richardson and Hugh Bonneville, who gets involved in a spoof of The Apprentice.

The impressive supporting cast also includes Mike Wozniak, Jason Lewis and Morgana Robinson.

Unreported World (C4, 7.30pm)

MILLIONS of schoolgirls across Africa are being manipulated, threatened and sexually abused by those who are supposed to be looking after them – their teachers. Kiki King visits Mozambique to investigate the disturbing phenomenon known as "sex for grades", where teachers force their female pupils to have sex with them in return for better grades – or even their deserved grades. As King discovers, the Mozambican Ministry of Education has found that 70 per cent of schoolgirls are either facing this kind of harassment or witnessing it. Last in the series.

Alan Carr's Happy Hour (C4, 8pm)

FRIDAY nights with Alan Carr used to mean his talk show Chatty Man, where the celebrities could call in for a post-watershed drink and a natter. But now he's moving to the earlier time of 8pm for his brand new series, which effectively gives him the chance to organise his own club night. Although there will still be celebrity interviews, there will also be stand-up comedy, live music and variety acts, all filmed in front of a specially invited studio. Channel 4 is promising us that it's the best Friday night out you can have without leaving the house – although despite the title, it seems that earlier timeslot means that the booze probably won't be flowing quite as freely as it did on Chatty Man.

Coastal Path (BBC2, 8.30pm)

WALKING England's South West Coast Path may not sound like much of a challenge for an explorer like Paul Rose, but at 650 miles, it's a major undertaking – and it turns out there are plenty of opportunities for adventure along the way. This week, he's in South Cornwall, which is the perfect place to try out the high-octane sport of coasteering. That essentially means exploring the rocky coastline by climbing, swimming or walking, which may not sound that extreme at first, but has the potential to get the adrenalin pumping. Paul will also be discovering one of the world's finest stages at the Minack theatre, as well as having a blast when he gets to fire Tudor cannons at Pendennis Castle in Falmouth.

Viv Hardwick