Mariah Carey stunned guests by bursting into song at a hotel this week.

The superstar singer was at The Carlyle Hotel in New York City with her husband Nick Cannon, American Idol co-star Randy Jackson and producer Jermaine Dupri on Wednesday.

She was overcome with emotion when she heard the classic songs being played by the in-house band and immediately took to the microphone.

"Mariah was loving the music, and the band invited her to join in," an insider told New York Post.

Tracks performed by the star included Summertime and Lullaby of Birdland.

Mariah had a great time, even posting a picture of herself posing with the band on Twitter.

She'd earlier performed at an event to kick off the American football season, where she surprised many by donning a miniscule dress and taking her dog on stage.

Mariah performed her new song Triumphant at the event and has taken to Twitter to thank her fans for supporting the release.

"Thank you so much to my UK fans for supporting Triumphant and making it #1 on the UK urban chart!!! This song for YOU! Stay Triumphant !!! (sic)" she wrote.

One fan asked Mariah whether she has plans to take to the road any time soon.

"Ireally want to! With the new album. Currently recording & it's quite diverse Dahhhling! Can't wait for [my fans] 2 hear! (sic)," she wrote.