Relive Olivia Newton-John and Barry Gibb's stunning rendition of 'How Can You Mend A Broken Heart'

Barry Gibb and Olivia Newton-John gave us plenty of magical music moments since they first joined forces in the '80s.

But their performance of the Bee Gee classic 'How Can You Mend A Broken Heart' from 2009 might just be our favourite.

Performing in Australia as part of the Sound Relief benefit concert in aid of the Victorian bushfires, headliner Gibb surprised the audience when he welcomed the late Grease star to the stage mid-set for a stunning rendition of the 1971 hit song.

Before belting the song out together, the 75-year-old singer described Olivia as "the greatest female singer in the world."

And we couldn't agree more!