Taylor Swift and Selena Gomez posed in a sexy Twitter photo recently.

Selena Gomez turned 21 on July 22...and Taylor Swift wished her a happy birthday by posting a snapshot of the pair at Swift's Rhode Island home.

Swift and Gomez are replicating a nude mermaid statue and posing on a bench at Swift's home in Watch Hill, Rhode Island.

Happy 21st birthday to my friend, and the closest thing I've ever had to a sister, @selenagomez!! pic.twitter.com/GhOgkl3kZ1

— Taylor Swift (@taylorswift13) July 22, 2013

While Taylor Swift and Selena Gomez may not have mermaid tails, the two look enough like sirens in the Twitter pic to confuse any landlubber.

The two beauties are also besties, and their friendship has reportedly helped both immeasurably.

"I met [Swift] when she was 18. This is before [Swift's 2008 album] Fearless came out, and it was absolutely incredible to see someone so successful and so humble," Gomez told People earlier this year. "I think she has been a big part of me kind of staying the way I am too."

How sweet is that?!

Taylor Swift and Selena Gomez look both seductive and playful in the photo with the nude mermaid statue. Sadly, however, they're clothed.