And he's spillin' the details!
"I don't know if you had heard, but I had done one for Barbara Walters all those years ago," he divulged Thursday on The Tonight Show With Jay Leno. "Very steamy. It had been a while and I had promised never to do it again, but Amanda's birthday was the night of one of the premieres for the movie in New York, so I was singing her 'Happy Birthday.'"
And surely that would have been gift enough, but Jackman opted to show off those Tony-winning dance skills of his.
"Really, she's the naughtiest, cheekiest girl," the Golden Globe nominee said of his Les Misérables costar, who had previously dished to E! News about how she could barely remember a thing because she was "so embarrassed."
A likely story.
He started singing softly, but then "started grinding it out for her," Jackman recalled. "She seemed happier, I don't know."
Well, we're happier after hearing him tell us about it!