It certainly looks as though Taylor Swift's next studio album will be full of surprises! In what seems like an unlikely pairing, British singer-songwriter Ed Sheeran took to his official Twitter account yesterday to tells fans he is indeed working with the country starlet on her highly-anticipated fourth album.

"Writing songs with a very cool artist today :)," The BRIT Award winner tweeted. Sheeran quickly clarified his mysterious tweet by adding, "In and out burger, defacing guitars and writing music with @taylorswift13."

The cross-genre collaboration isn't Swift's first in recent months. In addition to being the featured artist on rapper B.o.B's song 'Both of Us,' the country superstar has also teamed up with pop phenomenon Justin Bieber to pen a track for the young heartthrob's next album.

"It’s crazy, I mean I even wrote a song with Taylor Swift, so the whole album ranges differently," Bieber tells U.K. radio station Capital FM. “Everything doesn’t sound the same, everything’s different and [after] each song you won’t expect the next song to happen.”

No word yet on a release date for Swift's follow-up to her multi-platinum album, 'Speak Now,' but the singer does offer an insight on the lyrical direction of the project. In an interview with the New Yorker this past fall, Swift revealed that the songs she’s penned thus far for her 2012 album are “sad.”

“Being so busy, there’s not a lot of time to stop in the middle of the day and just kind of think about this feeling that you just realized about a relationship you had a year ago,” says Swift. “The ones I love the most end up happening very quickly.”

The new album is expected to be released this fall.