If you walk into Cape Town's Mount Nelson Hotel, you should pull your shoulders back and your stomach in, and look confident. You never know whom you might bump into. Through that big old front door important names have walked: Winston Churchill, Charlize Theron, Nelson Mandela, Daniel Radcliffe .Agatha Christie was once seen in the moonlit garden, muttering to herself and staring in disbelief at an albino squirrel. Margaret Thatcher used to have her hair styled at the hotel's Linda of London.I once saw Michael Bublé shaking hands with his president in the gents, which is so posh it looks like an apartment in Paris.Goodbye Grand Budapest Hotel, you're but a blip on the radar, and hello Happy Valley glamour.So what was I, a humble member of the lumpenproletariat doing here? Attending a play, the premiere ofAlexander McCall Smith's The Summer of 1946. McCall Smith is the author of The No1 Ladies' Detective Agency etcetera, ad infinitum.It's being staged at the decadent, lush Planet Bar Restaurant, quite a jolly idea that marries dinner and theatre in attractive surroundings.Directed by one of the city's top directors, Nicholas Ellenbogen, it's set around characters around the world finding their way home after the war, via Cape Town."All lovers of music," he says, "they gather over a drink at the Nellie to share songs and stories. It's a nostalgic feel-good play in three acts, performed between each course."The theatre dinner menu is created by Rudi Liebenberg, and starts off with bubbles and canapés in the Planet restaurant's Conservatory Bar, the one where Charlize Theron and Sean Penn allegedly had a teeny brouhaha.The menu includes roasted cauliflower soup with toasted almonds to start with, kob meunière as main, and warm apple cobbler, orange-blossom ice-cream and custard cream for dessert.Meanwhile, the show must go on, and it certainly does.On stage there are five young people camping it up in delightful old fashion, singing, acting, dancing, and playing the flute and harmonica, piano, saxophone and violin.It must be hard to compete with the occasional clinking of cutlery, which is why this sort of theatre experience could easily turn into a wild animal causing havoc. It doesn't, though, and the cast create a delicious extravaganza.As an ensemble they're all good, but two stand out, Cameron Robertson, alto and tenor sax, and Hilda Cronje, who tap-danced.Robertson sang Waltzing Matilda, a song that at times could border on cheesy,with such moving warmth and pathos that there was complete silence.Or did I hear Agatha Christie's ghost mutter to herself out there in the moonlit garden?Every Tuesday evening until June 9. Book at restaurantreservations.mnh@belmond.com. R450pp..