"This is so bad!" the singer told us. "Mine's been Steven Tyler since I was 7 and it started getting creepy at that point. Johnny Depp, who's now a man, or Steven Tyler, who's now a grandpa. Take your pick."
Her sister Maisy, on the other hand, felt very strongly about her crush: Justin Bieber. "He is beautiful and he's young."
Check out the video above for the sisters' first musical memory, which concert Maisy regrets missing and with who their dream duet partners.
The Nashville finale airs on Wednesday at 10/9c on ABC.