The actress learned she'd landed the role as a divorced single mum on her birthday, and Carey called her personally to congratulate her.

"She left me a voicemail," Chabert tells TV Guide. "It was the sweetest message, and she sang me 'Happy Birthday'. I've listened to it a thousand times and played it for everybody I know."

But the actress admits meeting her pop idol for the first time and then working with her really tested her nerves.

"We went to have dinner with her and the producers," Chabert adds. "I was so nervous on the car ride over that I touched up my makeup, like, 17 times - because I'm a legit fan. But she's so nice and warm.

"When I was shooting scenes with her, I didn't forget that she's Mariah Carey, but I was at ease."