Tabby Callaghan (born Trevor John O'Callaghan; 22 April 1981, County Sligo, Ireland) is an Irish musician.

[citation needed] The panel of judges, Simon Cowell, Louis Walsh and Sharon Osbourne, advised Callaghan to re-audition as a solo singer in order to proceed in the competition.

[2][3] After The X Factor, Callaghan participated in a fly-on-the-wall "rockumentary" titled What Tabby Did Next which was shown ITV in August 2005, coinciding with the release of his debut single in Ireland.

The A-side, "Number One", was an original track penned by Callaghan himself and Mark Hudson (who had worked with him on The X Factor).

The Cavern Club management then provided him with an old pair of boots in their office which had been left behind by Ronnie Wood of The Rolling Stones.