2008: Demi and Selena were on Barney & Friends together as children in the '90s, which was the start of their close friendship. But as they embarked on their Disney channel roles alongside Miley, it often appeared to be two against one — even though Demi and Miley hit it off on the set of Hannah Montana in 2007. Nick Jonas and Miley dated from 2006-2007 and not long after their breakup, Selena started dating Nick — feel the drama starting? Adding fuel to the fire, Miley made a video with her close friend Mandy making fun of Demi and Selena's video. Miley took down the video and apologised (kind of), though that was certainly the start of some major tension.
2009: Demi and Selena starred in their first film together called Princess Protection Program. In an interview with People, Selena said, "We enjoy doing everything together." While a solid amount of photos exist of Miley and Demi posing on the red carpet at events throughout the year, the same can't be said for Miley and Selena.
2010: When a fan asked Demi how Selena was doing, Demi responded "ask Taylor," an immediate sign that something was off for the former BFF's. In an interview with Girls Life in 2010, Demi responded to questions about their friendship saying, "We're both busy, and I wish the best for her. True friends don't let their friends or family be mean to you. If you can't trust somebody, you can't be friends with them."