• Demi Lovato and Selena Gomez's friendship dates back to when they both appeared on "Barney and Friends" in 2002. 
• Once inseparable, their relationship has faced ups and downs as both of their careers have progressed. 
• Although they've shown support for each other in recent years, Lovato confirmed that they're "not friends" in an April 2020 interview with Harper's Bazaar. 
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Demi Lovato and Selena Gomez have been linked for 18 years; their friendship spans back to when they both landed their first roles on "Barney and Friends." 

In their childhood and adolescence, the duo was inseparable. They supported each other as Disney Channel stars, costarred in a Disney Channel Original Movie (DCOM) together, and promoted each other's burgeoning music careers. But as their careers progressed, their relationship hasn't been completely straightforward.

They've exchanged public messages applauding each other's success in recent years, however Lovato confirmed that they're "not friends" in a Harper's Bazaar interview in April 2020. 

From their "Barney" days to today, here's everything we know about Gomez and Lovato's complicated friendship. 

2002: Lovato and Gomez became friends when they appeared on "Barney and Friends" together.

They both appeared on "Barney and Friends" from 2002 to 2004. Gomez was cast as Gianna on the show, and Lovato played Angela. 

In a 2017 interview with International Business Times, Fred Holmes, the show's director at the time, described the early bond between the girls, who he recalled always "laughing together hysterically" on set. 

"Very early on, you could just tell, they clicked," he said, adding, "Certain kids got along with other kids and they were just two of those that really clicked. They were pretty inseparable and ate lunch together and all those types of things."

2008: They began filming vlogs together and uploading them to YouTube.

As both of their acting careers took off — Gomez on Disney Channel's "Wizards of Waverly Place" and Lovato on the Disney movie "Camp Rock" — they began filming YouTube videos together. In the first video, they announced that they were costarring in the Disney Channel original movie "Princess Protection Program."

"This is my best friend in the entire world," Lovato said in the first video, and Gomez answered, "And this is my best friend ever since we were 7 years old."

In later videos, they showed off their friendship handshake and answered fans' questions.

After reading a fan's question asking what makes them best friends, Gomez replied, "I think really what makes her a true friend for me is just that she's honest with me, and she's always there for me, no matter if it's 3 in the morning, even if we're not saying anything on the phone, just to talk to her and tell her absolutely anything. And she's got the biggest heart ever."

"So do you!" Lovato responded.