Madonna is to host the Sound of Change Live concert - which features performances from stars including Beyonce and Jennifer Lopez - at Twickenham stadium next month.
The Hung Up hitmaker was "really keen" to be involved with the musical spectacular, which takes place on 1 June in aid of Chime for Change, which campaigns for improved education, health and justice for women and girls worldwide.
A source said: "Securing Madonna for the concert is a real coup.
"They didn't even dare to think that she might be interested, but as soon as she discovered the cause was empowering women, she was really keen."
Beyonce is headlining the concert and, following her reunion with Destiny's Child bandmates Kelly Rowland and Michelle Williams at the Superbowl halftime show earlier this year, it had been rumoured that she would perform with the group again, but instead she will take to the stage with her husband Jay-Z.
The source added to The Sun: "There's been a lot of buzz about Destiny's Child joining Beyonce on stage, but it's actually going to be Jay-Z."
Jennifer Lopez, Florence and the Machine, Rita Ora, Ellie Goulding, John Legend and Haim are among the performers at the four-hour musical spectacular, while other presenters on the night include James Franco, Blake Lively and Jada Pinkett-Smith.
Tickets for Sound of Change Live available here.