30 Seconds To Mars are celebrating after setting a new world record for performing the most shows during a single album cycle.

The group, fronted by Jared Leto, have played 309 concerts in just over two years while promoting This Is War, which was first released in December, 2009.

The band performed its 300th show at the Hammerstein Ballroom in New York City on 7 December (11), followed by a week of special gigs to celebrate the milestone - and Leto has thanked fans for their support during the mammoth trek.

In a post on his blog, he writes, "For over two years we have traveled (sic) this miraculous planet. Pushing relentlessly over mountains and seas, exploring this earth in the most unique of ways. All the while learning about this world, and ourselves, through all of you.

"Thank you for the dreams. Thank you for the memories. And thank you for sharing this unforgettable adventure with us. It was the journey of a lifetime and we are so grateful to you all for that."