Harrison posted a photograph of himself with Bachelorette finalist Arie Luyendyk Jr, along with the caption: "Hangin' [with] my boy @ariejr before we start shooting the new season of #bachelor".
© Instagram / @chrisbharrison
The Bachelor producer Mike Fleiss also confirmed that a candidate has been chosen and filming is underway, but did not reveal the man's identity.
He wrote: "Started shooting Bachelor 2013 this morning... We definitely picked a great guy," later adding: "He'll be the most shirtless bachelor - ever!!!"
© WENN / ABC
Racing driver Luyendyk Jr, who lost out to Jef Holm in the most recent series of The Bachelorette, has previously been linked with the new series of The Bachelor. However, he recently denied that he would be the show's next lead.
Sean Lowe, who finished third in The Bachelorette, is believed to be the favourite to be the next Bachelor.
Olympic swimmer Ryan Lochte has also expressed an interest in starring in the show.
The Bachelor is due to return to ABC in spring 2013.
