Noteworthy gigs by the Undertones since their 1999 reformation include performing at the Glastonbury Festival in June 2005, providing pre-match entertainment prior to kick-off at Celtic Park in the UEFA Champions League play-off between Celtic and Arsenal in August 2009 and, in March and April 2011, performing a series of UK gigs in which they played their debut album, "The Undertones," in its entirety as part of each show. This tour was timed to accompany a re-release of a double compilation album containing all of the A- and B-sides of their singles.