The wives stood for photographs on the Royal Opera House stage
The partners of G20 leaders have heard a reading by Harry Potter author JK Rowling, at an event hosted by prime minister Gordon Brown's wife Sarah.
They visited Covent Garden's Royal Opera House, where Ms Rowling entertained them with excerpts from her new book, The Tales Of Beedle The Bard.
Dancers rehearsing for a production of Giselle performed for the group of 13, including US First Lady Michelle Obama.
Ms Rowling was also a guest at a Downing Street dinner on Wednesday.
The women were greeted individually by Mrs Brown, wearing a blue dress, as they arrived at the opera house.
After the entertainment, they took to the building's main stage for a photograph.
Canadian Prime Minister Stephen Harper's wife Laureen declared: "I will never be on the stage, this is my one and only chance."
The group met the dancers before enjoying a private lunch.
Thanking the performers after a standing ovation, Mrs Brown said: "I think I can speak on behalf of all the G20 spouses when we say thank you so much.
"In this difficult time, with the difficult summit taking place down the road. You remind us all about the part that culture plays in keeping us all alive."
Among those missing from the event were French President Nicolas Sarkozy's wife Carla Bruni and German Chancellor Angela Merkel's husband Joachim Sauer, who have not accompanied their partners to London.
On Wednesday, Mrs Brown took Mrs Obama to see the Maggie's Cancer Care Centre at London's Charing Cross station.
Many of the spouses attended a meal later in Downing Street, in a separate room to their husbands, who held economic discussions while they ate.
Guests included Olympic gold medallist Dame Kelly Holmes, model Naomi Campbell and Gavin and Stacey actress Ruth Jones.