Rugby World Cup referee Nigel Williams will replace fellow Welshman Nigel Whitehouse as the match referee for the Pool 1 fixture between Leicester Tigers and Ulster at Welford Road on Saturday (kick-off 3.00pm).
Whitehouse has stood down from the fixture due to a family bereavement and an injury. Williams will be assisted by David R Davies and Haydn Davies, who will act as his touch judges.
It will be Williams' 16th Heineken Cup assignment and his first return to Leicester since he took charge of the tournament's 500th game, last season's quarter-final between the Tigers and Munster.
For a full biography on Nigel Williams, and to read his comments on the art of refereeing, please log on to www.ercrugby.com and click the "Whistle Blowers" box on the Heineken Cup news page.