The Britain's Got Talent sensation is getting ready to jet across the pond to appear with the American celeb on US TV show Dancing With The Stars, and she will then join him on stage in Sin City at the show he has been doing with his sister Marie since 2008.
Susan, 51 - who has been a fan of the Osmonds for years - told the Daily Mirror it's a dream come true, particularly because she has always wanted to take to the stage in Vegas.
The Scottish singer said: "I am ecstatic at the moment."
"I can't wait. Bring it on," she continued. "I'm looking forward to Vegas and you never know I may have a wee flutter in the casino. I will also be making sure I do the helicopter ride over the Grand Canyon.
"I've said since 2009 that I'd love to sing in Vegas and now singing with Donny in Vegas well, I'm over the moon."
Donny has teamed up with Susan for two tracks on her new album Standing Ovation, to be released on November 19.