Shania Twain ‘Having the Best Time’ as Idol Guest Judge
09/01/2009 AT 12:00 AM EDT
"She's loving American Idol. She's having the best time," says a source close to the singer, who is filling Paula Abdul's vacant seat during auditions Monday and Tuesday in the Windy City. "She and Simon have a really great rapport with each other. They're funny together."
Cowell isn't the only one having fun with Twain, 44. "The crew loved working with her," says an Idol source. "Everyone thought she was a great addition to the judges' table. She showed up in good spirits and had a lot of fun. She was clearly really excited to be a part of the day."
Twain's stint on the talent search capped an unusually public week for the typically private singer, who last week finally opened up about her relationship with Thiébaud. "She's the happiest I've seen her in years. I know he has a lot to do with it," says the Twain source, adding, "She's really pleased to be in the public eye again."
After finishing her Idol judging Tuesday, Twain will head home to Switzerland, where her son Eja, 8, is in school. Says the Twain source, "She'll continue writing songs and enjoying life." --Jason Lynch with reporting by Alexis Chiu Lisa IngassiaPeter Kramer/AP; Sthanlee B. Mirador/Shooting Star