ercrugby.com and James Mortimer 13.Nov.2012Getty Images
The all-Premiership clashes, starting at the Madejski Stadium in Round 3 on Saturday, 8 December, should go a long way to settling the group honours and automatic qualification for the knock-out stages.
"Bryn Evans is a very important player for the club," said London Irish Director of Rugby, Brian Smith.
"He runs our line-out and is a key member of the leadership group. On top of that Bryn brings a lot of rugby intelligence to the team and he's a very popular and respected member of the group.
"It's fantastic he's committed to the London Irish cause. He is one of the true believers."
The second row forward, who joined the Exiles in September 2011 from the Hurricanes in Super Rugby, has made 35 appearances for the Exiles, scoring three tries.
The Kiwi, who stands 196cm and weighs 115kg said: "I am so proud to be a part of this club, and I am looking forward to extending my time here by another two seasons.
"There is a very strong group of young players emerging with a huge amount of potential and I can really see the squad moving forward in the right direction with these guys around."