Complex sentence: Florence Welch was asked by Dido, who is actually pregnant, to perform "If I Rise" at the Academy Awards, she was joined by A. R. Rahman for the first live version of the song.
Split into simpler sentences: Florence Welch was asked by Dido, who was pregnant at the time, to perform "If I Rise" at the Academy Awards. She was joined by A. R. Rahman for the first live performance of the song.