London Irish have moved their Heineken Cup game with Leinster to Twickenham because of a fixture clash.
Irish share their ground, the Madejski Stadium, with Reading Football Club and the Leinster match clashed with the Royals' FA Cup campaign.
The round six game against defending champions Leinster will now take place on Saturday, 23 January.
London Irish head coach Toby Booth told the club's website: "This fixture is certainly worthy of the biggest stage."
He added: "We love playing our rugby at our home in Reading, but this change of location was unavoidable and we're delighted that more of our fans can come and support us on what promises to be an excellent evening of top class rugby."
Going to Twickenham Stadium is always an amazing experience for players and supporters alike and we're sure that the atmosphere is going to be fantastic
London Irish captain Bob Casey
The Exiles go into their round five clash against Scarlets having won three out of their four previous Heineken Cup games.
They will be hoping to overcome Scarlets, after narrowly losing 27-25 when the two sides met in round two.
London Irish captain and former Leinster player Bob Casey has said the players are looking forward to playing at the home of English international rugby.
"Of course it is a shame that we won't be able to play at our home ground but we are really excited that more people will be able to come and watch what will be a massive match for both clubs," he said.
"Going to Twickenham Stadium is always an amazing experience for players and supporters alike and we're sure that the atmosphere is going to be fantastic."
The club will automatically be reissuing tickets to all those who have purchased already.