It was battle of the boy bands in John Krasinski [1] and Anna Kendrick [2]'s episode of Lip Sync Battle last night. While Anna made it all about John's wife, Emily Blunt [3], during her performance of One Direction's "Steal My Girl," John threw it back a few decades — complete with a microphone headset — and performed *NSYNC's hit "Bye Bye Bye." While his dance moves were amazing in their own right, Anna managed to steal the show when she had a video montage of Emily play during her performance, which caused John to completely lose it, laughing as Anna ripped open her top to reveal a t-shirt with Emily's face on it. Check out the hilarious battle above, and then relive Anne Hathaway's headline-making "Wrecking Ball" performance [4] from last week's episode.