It will be Lewis' first Heineken Cup final but his third European final overall as he refereed the 2002 and 2005 European Challenge Cup finals.
"It is an absolute privilege to be entrusted with the Heineken Cup final," said the man who has also been named among the elite 12 referees for duty at 2007 Rugby World Cup 2007.
He was in charge eight days ago when London Wasps beat Northampton Saints in the Heineken Cup semi-final at the Ricoh Arena and he has already taken charge of more European matches than any other referee.
"The final promises to be a very special occasion with two English teams, for whom I have the greatest respect for, playing at their national ground," he said.
"I have refereed both clubs twice this year - Leicester in the Heineken Cup quarter-finals and at Twickenham in the final of the EDF Energy Cup, and Wasps in Heineken Cup matches in round six and then the semi-finals."
His 55 matches in ERC tournaments include a tournament record 44 Heineken Cup matches as well as 11 European Challenge Cup matches, following his European debut in the latter tournament when Gloucester played Bordeaux-Begles in 1996.
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