The singer announced plans to release 'Begin Again' on iTunes in the US on September 25, in support of her new album Red.
Swift introduced the track during an appearance on Good Morning America after revealing to US music magazine Rolling Stone that she wants to unveil her new record track by track.
"I want to unveil the songs one by one," Swift told the publication. "Starting this week I'm gonna start unveiling new music.
"I really want there to be so many surprises left on the record for when it comes out eventually, some collaborations that haven't been talked about and some songs that are definitely what make the album so unique."
Red will be Swift's fourth studio album and released in the UK on October 22 and a day later in the US.
Listen to a clip of Taylor Swift's new song 'Begin Again' below: