Camp Rock fans get excited!
Joining Demi on stage was her former flame and Disney co-star, Joe Jonas. Eek!
Asking her fans if they minded if she played a really old song (circa 2008), Demi launched into a rendition of 'This Is Me', a track from the movie, and surprised fans as Joe then joined her on stage to sing his part of the song.
Now that's a blast from the past!
Following his performance, Joe tweeted: "Tonight was amazing. Fun keeping this a secret @ddlovato @ Staples Centre" while Demi revealed it was the first time the pair have sung together in four years.
Sharing a picture of herself and Joe on stage, Demi said: "Thanks @joejonas for the awesome surprise!! #staplescenter #4yrssincewesangtogether #demiworldtour"
Having dated in the past, Demi and Joe have remained good friends despite their split back in 2010.
Speaking about her ex-boyfriend in an interview with ABC's Nightline last year, Demi said: "We were in a relationship and we broke up, and at one point, I was really mad at him... Now, I can fortunately say that he and his brother Nick have always been there for me and are literally family, like brothers … we have a great friendship."
Demi is now dating That '70s Show actor Wilmer Valderrama.
According to MTV, Joe's brother Nick has also got involved with Demi's tour as he is the creative and musical director for it.
Speaking about Nick's input, Demi said: "He threw out some ideas and they were really good, and we just thought, 'Why don't you just do the whole tour, please?... It's turned out amazing!"
It sure does sound amazing!
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Watch Demi and Joe singing 'This Is Me' in Camp Rock back in 2008: