It was a moment all right—though whether there's chemistry, we'll let you be the judge.
The appearance marked the Sin City debut for the Britain's Got Talent star who, when she wasn't dueting with her all-time idol, also performed a solo rendition of "Who I Was Born To Be" (they also performed "This Is the Moment" on Tuesday night's Dancing With the Stars).
Boyle also recorded two ditties for Osmond's new album, Standing Ovation: The Greatest Songs From the Stage, dropping Nov. 13.
All we can say is: Who needs Marie?!