There were a number of surprises during the Monday (May 21) season finale of American Idol, but one of the sweetest moments came when country star LeAnn Rimes surprised former contestant Layla Spring and her sister, Dyxie.

The crowd gasped as they saw Rimes walk out and toward the sibling duo, who were smack dab in the middle of singing "Blue." Both girls looked downright shocked at the chance to sing with Rimes, who made "Blue" a massive hit via her cover of the song in 1996.

After the show, Rimes expressed her love for the adorable singers on Instagram:

Spring also couldn’t seem to hold in her excitement about the moment, which caused judges Lionel Richie and Luke Bryan to stand and cheer with the rest of the crowd.

"What an amazing surprise, LeAnn Rimes!" Spring wrote alongside a picture of the three backstage after the performance. "We have grew up [sic] listening to your music ... and will cherish sharing the stage with you for a lifetime!"

The show ended with Top 2 American Idol finalists Caleb Lee Hutchinson and Maddie Poppe announcing live on television that they're a couple. Moments later, it was revealed that Poppe had won the season. Darius Rucker and Luke Bryan also performed Monday night.

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