Friday's TV highlights

It's now been 20 years since the UK won the Eurovision Song Contest - our last victors were Katrina and the Waves back in 1997 with Love Shine a Light. So that makes it all the more important that we find the right song to represent us this year, and the BBC are turning to the public to help with the search. Hosted by self-confessed Eurovision fan Mel Giedroyc from the Hammersmith Apollo, this live shows sees six short-listed acts taking to the stage in the hopes of impressing the viewers and a jury of music professionals. The panel will offer feedback on the songs - and some suggestions as to how they might be staged - before their scores are combined with the public vote to determine who will be flying the flag for the UK in Ukraine this year.

The World's Most Extraordinary Homes (BBC2, 9pm)

Piers Taylor and Caroline Quentin explore unusual homes built underground. In Greece, they view a house hidden beneath the landscape that still boasts stunning sea views. In the Swiss Alps, they visit a house made so invisible it has to be accessed via a tunnel. Next it's over to New Zealand's South Island to a house built underground to soften its impact on the landscape as well as withstand the threat of earthquakes, before the pair inspect a Dutch house created by deep excavation, which features a huge, light-filled open-plan living space. Last in the series.

Sound of Musicals with Neil Brand (BBC4, 9pm)

Some people might think the golden age of musical theatre was the era of Rodgers and Hammerstein, but in fact some of the longest-running, most globally successful productions actually came along in the 1980s and 1990s. Neil Brand concludes the series by looking at the rise of the all-conquering contemporary blockbuster, from Evita to Les Miserables and The Lion King. He also sees how these mega-musicals have met with unexpected competition from quirky hits such as The Rocky Horror Show and Avenue Q. Contributors include Tim Rice, Alan Menkin and Robert Lopez.

Tina & Bobby (ITV, 9pm)

The duo try to escape their marriage troubles by investing in their future, but a disastrous business venture mires them in debt just as Bobby's playing career starts to wane. Bobby winds up managing a lowly non-league side, and Tina dismisses rumours he's having an affair - until her worst fears are confirmed. When he confesses to loving the woman involved, her world collapses along with her marriage and she finds she must start her life afresh. Drama, starring Lorne MacFadyen and Michelle Keegan. Last in the series.

The Last Leg (C4, 10pm)

Thanks to their US Election and Christmas specials, it doesn't feel like Adam Hills, Alex Brooker and Josh Widdicombe have ever really been away. However, that doesn't mean we're not glad to have them back for a new, tenth series of the satirical comedy show, especially as recent events, including the inauguration of Donald Trump, mean there should be plenty of 'is it ok' questions for them to tackle. Luckily, they won't be dealing with deluge alone as they are joined by a celebrity guest - and this week it's former Doctor Who David Tennant who'll be reflecting on the week's headlines and assisting the trio in addressing the topics that some other shows might prefer to duck altogether.