Who knew these two were close gal pals? Sure, they're both on CW television shows (90210 and the upcoming Melrose Place), but we never would have guessed that Ashlee Simpson and Shenae Grimes were BFFs!

The ladies were snapped holding hands as they left the Troubadour to watch John Mayer perform last night, and even though they weren't super friendly with photogs, we did catch them giggling as they headed to Shenae's car! Hmm, but how would Jessica feel about her sister going to her ex-boyfriends concert? Maybe she doesn't care because she knows John and Ash's hubby Pete are buddies? Still, that's gotta sting...you know Jess probably wishes she was the one on Ash's arm!