There are several artists named GMT:

1. Guy McCoy Tormé (also known by the acronym GMT) is a British rock band formed by Robin Guy and former Gillan members John McCoy and Bernie Tormé.
MusicBrainz

2. An alias used by Guy Sigsworth for the g:mt Greenwich Mean Time movie soundtrack.
MusicBrainz

3. Santos De Castro & Paul Wright. Read more on Last.fm. User-contributed text is available under the Creative Commons By-SA License; additional terms may apply.