Selena Gomez and Demi Lovato used to be an inseperable pair, having starred in "Barney & Friends" together as children and grown up in the spotlight as Disney princesses and best friends. While they've grown apart over the years, the two have always remained on good terms, and most recently reunited behind-the-scenes of "The X-Factor."

"It's just the evidence of forever. No matter what," Gomez tweeted Lovato last night, along with an Instagram selfie of the two hugging and making kissy-faces for the camera. Gomez was on set of "X-Factor," a show in which Lovato is a returning judge and mentor, to tape her latest TV performance, which will air next week due to a recent voting mix-up.

"Love you SO much.. #14yrsStrong," Lovato tweeted in response, retweeting the latest photo of her and her friend, much to the surprise and delight of fans.

While Gomez was on "Wizards of Waverly Place," Lovato starred in her own Disney show, "Sonny With a Chance," and later the two filmed a Disney Channel Original Movie together, "Princess Protection Program," which aired in 2009 and was a big hit for the network. They also recorded and released a duet for the film, "One and the Same," which peaked at No. 82 on the Billboard Hot 100.

Lovato's song "Two Worlds Collide," which she wrote about her and Gomez's roles in the film, was also featured on the soundtrack, and has been dedicated to Gomez in several of her live performances.

Later that year, however, the two had a falling out, sources close to the stars claiming that Gomez was not in favor of Lovato's partying ways, and fans were saddened to see them begin to grow apart. But when Lovato entered treatment in 2010 for a number of issues including self-harm and an eating disorder, Gomez was one of the first people to call her.

"Selena...she called me crying when I was in there and was just so worried," Demi told Televisionet earlier this year. "I was like, 'Look, I should be the one crying, it's all good!'... But she was so worried and ever since then we've gotten closer."

Since then, while they haven't been spotted hanging out or making goofy YouTube videos like they used to, Gomez and Lovato have confirmed in multiple interviews that they'll always love and support each other.