The 'Britain's Got Talent' star will cover the Christmas carol 'O Come, All Ye Faithful', with the late singer.
Elvis' ex-wife Priscilla gave Susan her blessing to record the track, which is set for release on 8 December, with proceeds going to Save The Children.
"My dad and my whole family were Elvis fans and she gave me permission."
She added: "I do sometimes feel his presence when I sing the song, but who wouldn’t? I think he would be quite excited about the duet."
Meanwhile, it has also been announced that Susan is set to follow in the footsteps of fellow 'BGT' star Paul Potts with a film about her life.
'One Chance' - which sees James Corden playing the mobile phone shop worker turned opera singer in the biopic - has been met with widespread critical acclaim, and it seems Susan's story is set for a similar treatment.
"There are plans in operation for that, but that's for later on," she teased at a press conference for the launch of her Christmas single.