Pop stars grow up so fast.
Nick Jonas participated in Throwback Thursday by sharing an adorable pic of himself with ex-girlfriend, Miley Cyrus, back when she was Hannah Montana and he was in his siblings' boy band.
"When you're 13... hanging with your first crush and you're trying to play it cool," Nick, 23, Instagrammed. Calling out his sweaty T-shirt in the pic, he added the hashtag "#wheresmydeodorant."
Nick and Miley, 22, dated from 2006 to 2008 and have clearly remained friends. He's also stayed pals with his brother Joe's ex-girlfriend, Demi Lovato. In fact, the two are going on tour together next summer and have started their own record label.
WATCH: Selena Gomez Admits Her Gay Friends Encouraged Her to Date Nick Jonas
Nick is playing favorites. The youngest Jonas brother was asked to choose between Miley, Demi or Selena Gomez (also Nick's ex-girlfriend) in a game of "Lips, Marry Leave" -- a.k.a. "F**k, Marry, Kill."
"Demi, obviously wife, because we're like brother and sister and friends," he admitted to Britain's Capital FM. After his semi-incestuous comment, he added, "I'd prefer to spend life with her, as opposed to the others."
WATCH: Nick Jonas Gets Called Out by Ellen DeGeneres About the Kate Hudson Romance Rumors
In October, Nick was spotted sneaking into a party that Demi was throwing, and, coincidentally, his rumored love interest at the time, Kate Hudson, was also in attendance. Check out the pics from the stars' night out in New York City: