One late change to the teams, it's for the visitors with lock Matt Symons ruled out through illness, so Kearnan Myall starts at 5 and Will Rowlands comes onto the bench. 

All the Harlequins talk tonight is of the players making their final appearances for the club at The Stoop, Nick Evans and Karl Dickson, but two others have extended their stay in south-west London.

Ross Chisholm, who can play at full-back or on the wing, and scrum-half Charlie Mulchrone have both agreed new deals with Harlequins.

Leaders Wasps make two changes from the XV who ran in six tries at Bristol two weeks ago.

Dan Robson returns at scrum-half in place of Joe Simpson, while Thomas Young is at openside flanker, with Guy Thompson switching to number eight.  

Wasps are again captained by Joe Launchbury - perhaps the unluckiest of those left out of the Lions tour after such a strong Six Nations.

Image source, BBC Sport

Replacements: Cruse, McIntyre, Cooper-Woolley, Myall, Hughes, Simpson, Cipriani, Leiua.  

Harlequins are unchanged from the side who lost to Exeter a fortnight ago.

Former All-Blacks fly-half Nick Evans, 36, who is in the starting line-up, and Karl Dickson, 34, the one change to the replacements, will be making their final appearance for Quins at The Stoop, having both announced their retirement at the end of the season.  

The squad features two players of note from the Lions' squad announcement last week - Jamie Roberts, the Wales centre who was tipped for selection but missed out, and prop Kyle Sincker, for many a surprise pick. Both, undoubtedly, will have respective points to prove.

Image source, BBC Sport

Replacements: Gray, Lambert, Collier, Merrick, Ward, Dickson, Swiel, Alofa.  

Wasps have dazzled with their glittering array of back-line talent this season - no-one has scored more points than their 645 points, averaging above four tries a game. They can seal a home semi-final with victory tonight, and could secure top-spot too with a win if Exeter lose to Northampton tomorrow.

A different target for Harlequins,who have their eyes on automatic qualification for next season's European Champions Cup. They can retake sixth tonight but will have to repair the barricades of Fortress Stoop, after the walls were badly breached by Exeter a fortnight ago.

Some intriguing clashes coming up. England team-mates Chris Robshaw and James Haskell line up in the back rows and the muscle of Jamie Roberts marks the quicksilver feet of Kurtley Beale at inside centre.