Harlequins are unchanged from the side which beat Northampton Saints in the Aviva Premiership last weekend.
Among the replacements, Rob Buchanan comes in to provide cover at hooker, while George Lowe returns from injury and will look to make his first appearance since the 16th November.
Meanwhile, Irish have announced an unchanged starting XV for tomorrow afternoon's local derby.
Director of Rugby Brian Smith retains the starting line-up that played Leicester Tigers at Madejski Stadium last Saturday. There are three changes among the replacements where George Skivington returns from injury to cover the second row. Steven Shingler and today's signing Patrick Phibbs provide half-back cover.
Form: Harlequins have won their last three clashes against the Exiles, with the most recent victory coming back in October with a 28-31 victory at the Madejski Stadium. The two victories before that were both by seven points at The Stoop, highlighting the nature of these clashes. Irish have lost their last six matches in all competitions, whilst Harlequins have won their last five.
Harlequins: 15 Mike Brown, 14 Tom Williams, 13 Matt Hopper, 12 Tom Casson, 11 Ugo Monye, 10 Nick Evans, 9 Danny Care, 8 Nick Easter, 7 Chris Robshaw (c), 6 Maurie Fa'asavalu, 5 George Robson, 4 Olly Kohn, 3 James Johnston, 2 Joe Gray, 1 Joe Marler.
Replacements: 16 Rob Buchanan, 17 Mark Lambert, 18 Will Collier, 19 Charlie Matthews, 20 Tom Guest, 21 Karl Dickson, 22 Ben Botica, 23 George Lowe.
London Irish: 15 Tom Homer, 14 Topsy Ojo, 13 Jonathan Joseph, 12 Sailosi Tagicakibau, 11 Marland Yarde, 10 Ian Humphreys, 9 Darren Allinson ,8 Chris Hala'ufia, 7 Jebb Sinclair, 6 Declan Danaher (c), 5 Matt Garvey, 4 Bryn Evans, 3 Halani Aulika, 2 David Paice, 1 Max Lahiff.
Replacements: 16 Scott Lawson, 17.Jerry Yanuyanutawa, 18 Leo Halavatau, 19 George Skivington, 20 Jamie Gibson, 21 Guy Armitage, 22 Steven Shingler, 23 Pat Phibbs.
Date: Saturday , December 29
Venue: Twickenham Stadium
Kick-off: 14:15 GMT
Referee: Greg Garner
Assistant referees: Nigel Carrick, Roy Maybank
Television match official: Geoffrey Warren