Taylor Swift's 'Everything Has Changed' Duet With Ed Sheeran Has Leaked (AUDIO)

Taylor Swift's "Everything Has Changed" -- a duet between the pop star and British crooner Ed Sheeran -- has leaked online, just four days before the release of Swift's newest album, "Red." The song was famously written while the two singers were just casually chilling on a trampoline.

"We, for real, [were] sitting on my trampoline in my backyard cause we had been writing a song and I was like 'Hey, I just got a trampoline. You want to see it?' And so, he brought the guitar for some reason. We ended up writing an entire song out there," Swift told MTV. "For portions of the song, [we were bouncing around] 'cause it's a trampoline and it's fun, and the combined maturity level of both of us is 8 years old."

"Everything Has Changed" is just the latest "Red" song to reach the internet. Swift had previously released "We Are Never Ever Getting Back Together," "Begin Again," "State of Grace," "I Knew You Were Trouble" and "Red," the album's title track.

Listen above; "Red" is out on Oct. 22.

Taylor Swift's 'Surprised' Face