The Real Marigold Hotel (BBC One, 9pm)

Eight famous pensioners meeting at Heathrow's Terminal 5 might not sound like the stuff of top TV, but within the first few minutes of this new series, it's hard not to be hooked.

There are now more OAPs than ever, so little wonder shows such as The Real Marigold Hotel have a built-in audience. The Best Exotic Marigold Hotel films which inspired this hit series have already proved that, while the vibrant colours of India are a great antidote to the grey skies we have to endure in Blighty.

Amanda Barrie, Dennis Taylor, Rustie Lee, Miriam Stoppard, Bill Oddie, Sheila Ferguson and Paul Nicholas are among the latest recruits travelling thousands of miles to make a new home in Kochi, a city in the southwest Indian state Kerala.

"I've never been to India, so why don't I give it a crack?" enthuses Sheila. Paul is also embracing the new experience. "I'm going there almost as a child, with my eyes wide open," he explains.

While Rustie and Miriam seem charmed by their first days here, the oldest member of the group at 87, finds dealing with the realities of living in India unsettling.

The one thing most celebrity travelogues need is scenes of the stars messing about in boats, and this new run does not disappoint.

It's a fascinating sight as they travel on traditional houseboats through the world famous backwaters, gliding along the vast waterways that crisscross through the villages and jungles. Lionel starts to warm to the experience, and likens the magical setting to "the garden of Eden".

Their first week is rounded off with a party to meet the neighbours. Several members of the group put on a performance for their new friends and everyone takes a moment to reflect on their time in India.

Can our celebs enjoy a more rewarding retirement than in the UK? That remains to be seen, though as a more gentle, exotic take on the Big Brother-style reality format, it offers a welcome change as eclectic characters either bond or get one another's backs up.

Who Do You Think You Are? (BBC1, 8pm)

Warwick Davis starts his research with his paternal grandmother Edith, who led to his big break at the age of 11 when she heard a radio advert. That advert was 'looking for short people to appear in Return of the Jedi', and Warwick was catapulted to stardom, continuing his acting career in the likes of Labyrinth and Willow. He takes a non-judgemental approach as he researches the family line stretching back from Edith, finding humanity and humour in some uncomfortable stories, while on his maternal side, he finds out about a postman who lived a double life.

Hospital (BBC2, 9pm)

In the final episode of the series, surgeons are forced to use unconventional methods to get their operations completed against the odds. At Hammersmith Hospital, 31-year-old Jennifer is taking part in a groundbreaking scheme, as she donates her own kidney to save her husband Elliot's life. Meanwhile at St Mary's, 84-year-old Betty arrives to have her bowel cancer removed, but colorectal surgeon George Reese has to decide whether it is safe to go ahead with her operation as there are no beds available for her to recover in. Last in the series.

I'm 21 But Look 61: Extraordinary People (C5, 10pm)

It might not be the catchiest title in the world, but for at least the content is far more worthy. For anyone whose heart went out to South Yorkshire teenager Zara Hartshorn from when the first part of this strand was shown, then now is a chance to play catch up. For newcomers, Zara has a rare genetic condition that left her skin loose and wrinkly. In short: it made her look like a much older woman. However, help was at hand because an American surgeon received news of the Rotherham girl's plight and offered to assist. In this film we follow Zara and her family as they cope with lipodystrophy, the condition that affects them all. Have those hankies at the ready as you may need them.