Harrington who won her second consecutive Olympic gold medal in the boxing last month, was met with a chorus of 'Ole, Ole' Ole', as she joined the trio on stage. Following her victory in Paris, Harrington had led the crowd into a rendition of 'Grace'.
However on this occasion, Harrington left this singing up to the Wolfe Tones.
Harrington's association with The Wolfe Tones goes back a while, having been invited to perform with the band by frontman Brian Warfield during their shows at the 3Arena last October.
Along with the Wolfe Tones, Kylie Minogue, Raye, Tom Grennan, The Stranglers and others performed on the Main Stage on Sunday.