Mike Brown starts at full-back and will make his 200th appearance for Harlequins in their Heineken Cup clash against Biarritz.
Jordan Turner-Hall and George Lowe also renew their centre partnership in midfield.
Among the forwards, there is one change as Tom Guest starts at number eight and is joined in the back-row with Maurie Fa'asavalu and captain, Chris Robshaw.
Luke Wallace is named among the replacements, while Ollie Lindsay-Hague will look to make his first appearance in the Heineken Cup.
The reigning English champions are the number one ranked side in the quarter-finals shakedown at the moment but a victory over the Top 14 side at the imposing Parc des Sports Aguilera would send a real message out to the rest of Europe and could ensure a meeting with the lowest ranked side in April.
Meanwhile, Taku Ngwenya returns to the Biarritz starting line-up on the right wing with Iain Balshaw reverting to full-back.
Former London Wasps prop Ben Broster starts at tighthead with Fabien Barcella on the opposite side of the scrum, with Imanol Harinodorquy returning at number eight and Raphael Lakafia moving to openside flanker.
Qualification is a long shot for the French side, who were Heineken Cup finalists in 2006 and 2010, and they simply have to beat 'Quins to come into the reckoning as qualifiers for the Amlin Challenge Cup quarter-finals.
They will also be looking for revenge for their 40-13 defeat to Harlequins in the Pool opener at the Stoop back in October.
The Frenchmen have been defeated only once at Stade Aguilera in the Heineken Cup since 2001 - 6-10 to Cardiff Blues on 13 December 2008.
Biarritz: 15 Iain Balshaw, 14 Taku Ngwenya, 13 BenoÃ®t Baby, 12 Damien Traille, 11 Aled Brew, 10 Jean-Pascal Barraque, 9 Dimitri Yachvili, 8 Imanol Harinordoquy, 7 Raphael Lakafia, 6 Wenceslas Lauret, 5 Pelu Taele, 4 Thibault Dubarry, 3 Ben Broster, 2 Arnaud Heguy, 1 Fabien Barcella.
Replacements: 16 Jean-Philippe Genevois, 17 Thomas Synaeghel, 18 EugÃ¨ne Van Staden, 19 Erik Lund, 20 Talalelei Gray, 21 Yann Lesgourgues, 22 Julien Peyrelongue, 23 SeremaÃ¯a Burotu.
Harlequins: 15 Mike Brown, 14 Tom Williams, 13 George Lowe, 12 Jordan Turner-Hall, 11 Ugo Monye, 10 Nick Evans, 9 Danny Care, 8 Tom Guest, 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 Luke Wallace, 21 Karl Dickson, 22 Ben Botica, 23 Ollie Lindsay-Hague.
Date: Friday, January 18
Venue: Stade AguilÃ©ra
Kick-off: 21:00 (20:00 GMT)
Referee: John Lacey (Ireland)
Assistant referees: Paul Haycock (Ireland), Michael Black (Ireland)
Television match official: Seamus Flannery (Ireland)