Singer and former Neighbours star Delta Goodrem persuaded Olivia, who is battling stage four metastatic breast cancer, to sing Merry Christmas To You on her Only Santa Knows album.
Delta, 36, who also fought cancer when she was diagnosed with Hodgkin lymphoma aged just 18, first sang with Olivia in 2008 to raise funds for the Grease star's cancer charity.Dame Olivia, 72, said of their latest duet: "I haven't sung for two years in public and I didn't think I would ever sing again."It was not something in my mind and I just haven't been singing.