On last night's American Idol on FOX, contestant Sam Woolf revealed that one of his biggest celebrity crushes was pop star Ariana Grande. Later on in the show, as host Ryan Seacrest feigned audio issues just before Woolf's performance, Grande herself ran on stage offering the red-faced teen a microphone.

She went on to give him a good luck hug, just before he began his performance of Ed Sheeran's 'Sing.' Check out the surprise appearance below!

http://www.youtube.com/watch?v=b82imzCcGW4