Carla Bruni-Sarkozy returns to stage for Mandela concert Carla Bruni-Sarkozy

Carla Bruni-Sarkozy returned to the stage for the first time since becoming France's first lady to honour former South African president Nelson Mandela. 

The anti-apartheid leader's 91st birthday Saturday sparked a concert full of A-list celebrities at New York's Radio City Music Hall, even though Mandela himself could not attend.

The wife of French President Nicolas Sarkozy performed her hit, "Quelqu'un m'a dit" (Someone told me), with British guitarist Dave Stewart. She also sang a duet of Bob Dylan's "Blowin' in the Wind".

Organisers of the charity concert want Mandela's birthday July 18 to become an annual international Mandela Day to raise money for children, people living with AIDS and others in need.