The Celtic Tenors is an Irish trio of tenor singers. The trio comprises Matthew “Gilly” Gilsenan, James Nelson, and Daryl Simpson. Known for their signature harmony-rich style, they blend opera, classical, Irish traditional, and pop influences. The group was formed in 1999 by Matthew Gilsenan, James Nelson, and Niall Morris. Niall left the group in 2006 and was replaced by Daryl Simpson.