Among Dame Shirley's best-known hits are Goldfinger and Big Spender
Dame Shirley Bassey is in hospital recovering from an emergency operation on her stomach, her spokesman has said.
The 71-year-old was admitted to hospital in Monaco, where she lives, with abdominal pains in the middle of the night last week.
She was "making a good recovery and doctors are happy with her progress", spokesman Paul Carey said.
Dame Shirley has enjoyed chart success since the late 1950s and sang the theme tunes to three James Bond films.
As well as those songs, for Goldfinger, Diamonds Are Forever and Moonraker, she is known for hits such as Big Spender and History Repeating.
Mr Carey said that the Welsh-born singer, who was made a Dame in 1999, had "an emergency operation to relieve stomach complications, after complaining of abdominal pain".
She is expected to recover in time for her performance at Nelson Mandela's 90th birthday concert in Hyde Park in London next month.
Among her most recent gigs was one at last year's Glastonbury festival, where she arrived in a helicopter and wore diamond-encrusted wellington boots.