Last time I saw the ad. - it doesn't seem to be running at the moment - it was Seal, the bald gentleman with the acoustic guitar. If there is someone else, please re-post with a description, and someone will advise you.
As far as I know the song was originally a 1975 (or thereabouts) song done by the band Supertramp and then recently used for the Gap commercial. If you liked the advert version then the original is probably better and well worth a listen.