Celtic Thunder is a singing group composed of six male soloists who perform both solo and ensemble numbers. Their latest album saw them being joined by Neil Byrne, who had played guitar and sang backup on the previous albums. Celtic Thunder debuted in August 2007 at The Helix in Dublin, Ireland. They are accompanied by the Celtic Concert Orchestra under the direction of Phil Coulter, the musical director of the group.

Since the group's formation, Celtic Thunder has released five albums: Celtic Thunder, Act Two, Take Me Home, It's Entertainment, Christmas as well as three live performances on DVD entitled Celtic Thunder: The Show , Take Me Home, It's Entertainment!, and Christmas In December 2009 Billboard magazine named Celtic Thunder Top World Album Artist. Their first three albums also placed in the Top 10 for World Albums.

Celtic Thunder is known for its eclectic style with songs ranging from a soloist to an ensemble focus. The group is backed by the Celtic Thunder Band on their concert tours, and their live shows are known for the use of dramatic effects via lighting and choreography as well as a stage set resembling an ancient stone pathway suggestive of those referenced in Celtic lore.

In March 2009, Celtic Thunder opened the Saint Patrick's Day Parade in New York City, and later that day performed for President Obama, Mrs. Obama and Taoiseach, Brian Cowen at the White House.

On Nov. 28, 2010, Celtic Thunder member Paul Byrom announced his resignation from the group as to begin a solo career for himself. He will leave the group when the 2010 concert tour is over. Byrom will begin his solo career in the United States, where he has the strongest fan base. Byrom hopes his fan base from Celtic Thunder would carry on into his solo career.

The members of Celtic Thunder are (in alphabetical order of family name):

Paul M. Byrom (born April 11, 1979) is from Dublin, Ireland. In addition to Celtic Thunder, he has also performed at major sporting events in Ireland and abroad, including singing at the All Ireland Finals in Dublin's Croke Park and at Heinz Field for a Pittsburgh Steelers game in the USA. He has also performed for Ireland's President, Mary McAleese, and for Emperor Akihito of Japan. Paul has released two albums: Velvet and I'll Be Home For Christmas It has been confirmed Paul will resign and pursue a solo career in the US once the 2010 Celtic Thunder tour is over. He was replaced by Emmet Cahill.

Emmet Cahill Auditioned for Celtic Thunder in June 2010. Asked to join after Paul Byrom announced his resignation.

George Donaldson (born February 1, 1969) is the oldest member of the group and is a well-known balladeer, guitarist and flautist from Glasgow, Scotland. At Scotland's Celtic Park, Donaldson played to 65,000 fans at the opening match of the 2000-2001 season.

Ryan J. Kelly (born November 6, 1978) is from The Moy, County Tyrone, Northern Ireland. He holds two degrees from the Queen's University Belfast, having earned a Bachelor of Science in Accounting and also a Graduate Diploma in Advanced Accounting, qualifying Ryan to be a chartered accountant. In the fall of 2010 Ryan released his solo album "In Time".

Keith R. Harkin, (born June 10, 1986), is from Derry, Northern Ireland. He plays the guitar and has written one of the songs for Celtic Thunder: "Lauren and I". Keith has now recorded more original songs apart from Celtic Thunder, some titles include: How I Wish and All Day Long.

Damian J. McGinty, Jr. (born September 9, 1992) is the youngest member of the group and is from Derry, Northern Ireland. He recorded the first Celtic Thunder album when he was fourteen years old. Since then McGinty's voice has matured, and he has gone from a tenor, to a baritone/bass. His inspirations are Michael Buble, Dean Martin and Frank Sinatra.