Meanwhile, experienced Welsh referee Nigel Owens will officiate in the derby game at the RDS between Leinster and Munster on Saturday (kick-off 8pm).
Clancy made his Magners League refereeing debut in 2004, when he controlled the game between the Borders and Newport Gwent Dragons. He has since gone on to referee in 35 Magners League matches.
One of the world's top 19 Test officials, Clancy made his representative debut in June 2008, taking charge of the South Africa v Italy Test.
Owens, who earlier this week was appointed to the new position of National Academy Referee Coach by the Welsh Rugby Union, refereed his first international game in Osaka in 2005 when Japan hosted Ireland.
The Borders also featured in Owens' first Magners League game, when they played Connacht back in August 2002.
The referee for the last two Heineken Cup finals, which were won by Munster in 2008 and Leinster in 2009, he was also in charge of Leinster's recent Heineken Cup semi-final defeat in Toulouse and Munster's quarter-final triumph at home over Northampton Saints.
MAGNERS LEAGUE SEMI-FINALS - MATCH OFFICIAL APPOINTMENTS:
Friday, May 14 -
Ospreys v Glasgow Warriors, Liberty Stadium, 7.05pm (live Setanta Sports Ireland/BBC Wales)
Referee: George Clancy (Ireland)
Assistant Referees: Dudley Phillips, Leo Colgan (both Ireland)
Television Match Official: Bertie Smith (Ireland)
Saturday, May 15 -
LEINSTER v MUNSTER, the RDS, 8pm (live Setanta Sports Ireland/S4C)
Referee: Nigel Owens (Wales)
Assistant Referees: James Jones, Nigel Whitehouse (both Wales)
Television Match Official: Hugh Watkins (Wales)