Madonna proves she is a proud mom. The singer started her highly anticipated Celebration Tour in high spirits at the London 02 Arena, singing her hit songs and surprising the audience with an incredible performance and a sweet moment, bringing her daughters Lourdes Leon, Estere, and Mercy James to the stage.Fans of the singer showed their excitement after Madonna invited her kids to take the stage, with Estere showing her dance moves and making the crowd go crazy, while Lourdes and Madonna cheered.