Oh, boy! Jennifer Lopez seems so in love with her sexy young beau Casper Smart.

The 42-year-old songstress hit the stage with the 24-year-old dancer during last night's American Idol show for a steamy performance of her new single "Dance Again."

After the performance, JLo told the audience, "He's so cute."

We love seeing Ms. Lopez so in love! Click thru to see their electrifying AI performance.