Harlequins welcome back England internationals Marcus Smith, Joe Marchant and Cadan Murley for their Gallagher Premiership clash with Exeter Chiefs at Twickenham Stadium on Saturday, a key trio in their qualification for the Heineken Champions Cup Round of 16.

Fly-half Smith tallied 21 points in two Heineken Champions Cup pool stage games as Quins set up a knockout stage trip to DHL Stormers, while wing Murley scored three tries and centre Marchant played the full 80 minutes in all four of their matches so far.

It is less than a month until Quins’ Round of 16 visit to South Africa on April 1, and they’ll be keen for their big names to hit form in Saturday’s annual ‘Big Game’ at the home of English rugby.

Hooker George Head, lock Stephan Lewies and flanker Jack Kenningham also come in for Quins, while Danny Care continues at scrum-half for his 226th Premiership appearance, moving him second in the all-time list.

Exeter, who host Montpellier Hérault Rugby in the Heineken Champions Cup on April 2, also have internationals returning to their XV in Scotland’s Jonny Gray and Wales’ Dafydd Jenkins, who partner in the second row. Wales’ Christ Tshiunza is back at openside flanker.

Leicester Tigers are the other Heineken Champions Cup outfit in Premiership action on Saturday – Richard Wigglesworth’s side, who entertain Edinburgh Rugby in the Round of 16 on March 31, host Bath Rugby.

Wales’ Tommy Reffell is reinstated at openside flanker, while Harry Simmons, who crossed for his maiden Heineken Champions Cup tries in this season’s pool stage, is named on the wing.

There are further Heineken Champions Cup contenders involved in Saturday’s United Rugby Championship (URC) fixtures – two South African EPCR debutants face off at DHL Stadium as DHL Stormers welcome Cell C Sharks.

Wing Angelo Davids is back for DHL Stormers, while a much-changed Cell C Sharks side is captained by 25-year-old fly-half Curwin Bosch, the second-highest points-scorer in this season’s Heineken Champions Cup.

Elsewhere, Vodacom Bulls, the other South African team debuting in the Heineken Champions Cup this campaign, have brought in prop Dylan Smith, flanker WJ Steenkamp and wing Sibongile Novuka as they play Emirates Lions at Loftus Versfeld.

Another all-Heineken Champions Cup contest sees Edinburgh Rugby host Leinster Rugby, with the home side welcoming back prolific full-back Emiliano Boffelli along with Scotland lock Sam Skinner and flankers Hamish Watson and Luke Crosbie.

There are two tweaks for Leinster amid injury returns for full-back Ciarán Frawley and lock Jason Jenkins, the latter of whom will make his first start since their Heineken Champions Cup opener at Racing 92 in December.

Flanker Dan Lydiate and centre Keiran Williams are among those called in by Ospreys as they host Benetton Rugby, while hooker Rob Herring is back to captain Ulster Rugby as they head to Cardiff Rugby.

In the TOP 14 on Saturday, Montpellier are at home to ASM Clermont Auvergne and Stade Rochelais travel to Section Paloise.

Two Heineken Champions Cup heavyweights feature in Sunday’s domestic games – lock Nick Isiekwe and centre Nick Tompinks return for Saracens as they visit Sale Sharks in the Premiership, while Stade Toulousain are away at Racing 92 in the TOP 14.