Harlequins star George Lowe has been named in the England U20s side for tomorrow's IRB Junior World Championship semi-final.

James Gaskell returns to the starting line-up for the clash.

The Sale Sharks lock takes over from Gloucester's Dan Williams in the second row against South Africa in Tokyo (11am BST).

The only other change to the matchday squad sees wing Jack Cobden replace his Leicester Tigers teammate Greig Tonks on the bench.

Head coach Mark Mapletoft admitted he had some 'tough calls' to make after England's 52-7 win over Samoa in the final Pool B match, particularly among the forwards.

London Irish James Clark starts a second Under 20 game in succession for the first time, while Bath flanker Josh Ovens has pushed hard for inclusion.

"Everybody's had an opportunity to play and we feel that this side is the strongest one we can put out for this game," said Mapletoft.

"James Gaskell comes back and that's hard on Dan Williams, who's done well, but James has had an outstanding season for us.

"There are a number of other tough calls in areas like the back row where Josh Ovens has done well all season.

"James Clark produced a good strong performance on Saturday, scrummed well, out lineout was good and South Africa will be a big threat in the tight.

"It's another tough call but Jamie George sitting on the bench gives us a good option in the second half."

"South Africa will pose us a massive physical challenge and their game is very strong at the moment if you look at the World Cup, the Sevens, Super 14. They've been very successful in age group world cups in the time I've been involved.

"They've got good halfbacks, they're big and strong in the front row, lots of quality and good players. Even at 20-0 down in their last game against France they didn't give up and ended up winning the game comfortably.

"We know we've stepped up and moved through the gears nicely. Now we've got to step up again and move it on another notch and it would be great to be able to do that tomorrow night."

England Under 20 15 Tom Homer (London Irish) 14 George Lowe (Harlequins) 13 Henry Trinder (Gloucester Rugby) 12 Luke Eves (Bristol Rugby) 11 Charlie Sharples (Gloucester Rugby) 10 Rory Clegg (Newcastle Falcons) 9 Ben Youngs (Leicester Tigers) 1 Ben Moon (Exeter Chiefs) 2 James Clark (London Irish) 3 Bob Baker (London Wasps) 4 Graham Kitchener (Worcester Warriors) 5 James Gaskell (Sale Sharks) 6 Courtney Lawes (Northampton Saints) 7 Calum Clark (Leeds Carnegie, captain) 8 Carl Fearns (Sale Sharks) Replacements 16 Jamie George (Saracens) 17 Shaun Knight (Gloucester Rugby) 18 Dan Williams (Gloucester Rugby) 19 Josh Ovens (Bath Rugby) 20 Dave Lewis (Gloucester Rugby) 21 Rob Miller (Newcastle Falcons) 22 Jack Cobden (Leicester Tigers)