British art-rockers Radiohead surprised fans Thursday night with a webcast from their studio that included a live acoustic performance of a new song.

According to the fansite FollowMeAround.com, the webcast also featured the bandmates, including singer Thom Yorke, dancing for the camera, DJing nearly 40 songs, writing out messages on paper and playing with puppets made from socks. The webcast reportedly started at 6 p.m. EST and lasted three and a half hours.

The new song was "Knives Out," according to the fansite, which cited the band's producer, Nigel Godrich, as the source of the information. The site tells fans that "bits and pieces" of the song's lyrics are available at the official Radiohead.com site and directs them to a page titled "we boild the head."

A posting on FollowMeAround.com from a fan with the user name Pleasantly Blue, titled "Overwhelming inexplicable feelings," stated: "I can't believe I am listening to 'Knives Out.' I am crying ... I can't stop ... such overwhelming happiness."

Another fan wrote in response to Pleasantly Blue, "I couldn't stop smiling, even if someone held a gun to my head, still wouldn't/couldn't stop smiling. I also was crying."

Radiohead are recording the follow-up to 1997's critically acclaimed OK Computer, featuring the hit "Karma Police" (RealAudio excerpt).

Guitarist Ed O'Brien, who has been keeping an online journal of the band's recording sessions on the group's official website, described "Knives Out" as "sounding quite 'Smiths-esque', especially [drummer Phil Selway] who has got that Mike Joyce [drummer for the Smiths] thing down to a tee."

The band apparently did not give fans any advance notice of the webcast other than a posting last week that suggested they download a certain audio player.

Representatives at Capitol Records confirmed that the webcast occurred but said it was as surprise to them as well.

Radiohead's as-yet untitled new album is slated for a summer release, Lewis Jamison, a UK spokesperson for the band, said recently.