Selena Gomez and Taylor Swift are best friend goals.

The female singers have been friends for years and, this week, they proved that they are closer than ever. On Wednesday, Dec. 13, Gomez posted a sweet message for Swift who celebrated her 28th birthday.

"I'm glad you were born. You write all the thoughts some aren't able to articulate. (Me!) Thank you for giving voice to this world that is authentic and inspiring," she wrote on an Instagram post. "I wish some knew how big your heart actually is.. it's fierce, bold and freaking wild with light. I'm glad you protect that. Love you [Taylor Swift]."

Friends Forever

Gomez met Swift years ago when they were just teenagers and they have their exes to thank for their meeting. Swift, then 18, was dating Joe Jonas and Gomez, around 16 years old, was with Nick Jonas. The two met backstage during their boyfriends' concert.

While their relationship with Joe and Nick did not stand the test of time, their friendship did. Several boyfriends later, Gomez and Swift still hang out and send sweet birthday messages to each other.

Growing Up

Swift has a dozen of reasons to celebrate this year. The 28-year-old has released her sixth studio album, Reputation, last month. While it received mixed reviews from fans and music critics, the album immediately landed at the No. 1 spot of Billboard 200 a week after it was launched.

The "Look What You Made Me Do" singer was also among the women recognized by Time as the 2017 Person of the Year. The pop star stood alongside Ashley Judd and Rose McGowan, the women who exposed decades of sexual assault cases against movie mogul Harvey Weinstein, on the cover of the magazine.

Earlier this year, Swift won a sexual assault trial against disc jockey, David Mueller. She accused the radio host during a meet-and-greet before a concert in Denver.

According to Swift, Mueller reached under her skirt and grabbed her butt while posing for a photo. She asked for a $1 in damages.

On a post on Instagram, Swift thanked her fans for an incredible year.

"I couldn't have asked for a better year, all thanks to you," she wrote. "Thanks for all the birthday wishes. Can't wait to see what 28 will be like. See you on tour."

Swift kicks off her upcoming tour for her album, Reputation, soon. She will visit 33 locations across North America. Tickets are now on sale.