Kevin Joseph O'Brien (born 4 March 1984) is an Irish all-rounder who plays for Railway Union Cricket Club and Somerset County Cricket Club.,he also holds the record for the fastest century ever scored at a World Cup, coming from 50 balls against England on 2 March 2011. An all-rounder, O'Brien is an aggressive right-handed middle to lower order batsman and a right-arm medium-fast bowler. He made his One Day International debut in 2006 in Ireland's inaugural match. O'Brien played for Nottinghamshire in 2009, and in 2010 was awarded a contract with Cricket Ireland, making him one of the six players with a full-time contract with the board. He has been Ireland's vice-captain since January 2012.His brother,Neil O'Brien also plays for Ireland and is the wicket-keeper of the team.