Star Trek icon William Shatner has collaborated with country music star Vince Gill, Foreigner's Mick Jones and guitarist Steve Vai for a new prog-rock album.

The acting veteran penned the lyrics for all the songs on the upcoming concept album, Ponder The Mystery, which explores themes such as "ageing, depression, love and beauty", according to a press release.

Shatner describes the album as "quite possibly the most creative thing I have ever done".

Ponder The Mystery is due out on 8 October (13).