The Senior Academy pair - who have both signed first team contracts for the next two years - are part of a 28-man squad to be coached by Rob Hunter and Nick Walshe.
England have a good recent record in the IRB Junior World Championships, having made the final in three of the past four years. But the reigning Grand Slam champions will have a tough challenge on their hands in 2012, with their third group game being against the hosts, South Africa.
England will play the Baby Boks in Stellenbosch on Tuesday, June 12th, with the same venue also hosting England's second group game against Ireland on Friday, June 8th. England open their campaign against Italy in Cape Town on Monday, June 4th.
All of the games will be shown live on Sky Sports.
Head coach Hunter is pleased with the players at his disposal as they look to better last season's second place finish.
"Competition for places has been high and some good players have missed out, however we're very pleased with the 28 selected," he said. "The games come thick and fast in this tournament, we've got a tough group and we're excited by that challenge.
"We have two huge games before we come up against South Africa, but that match stands out for the experience of playing them in front of their home support. For now though all our attention is on that first game against Italy, each year they improve and we'll need to be fully focused."
ENGLAND U20 IRB JUNIOR WORLD CHAMPIONSHIP SQUAD
Forwards
Dominic Barrow (Leeds Carnegie)
Koree Britton (Gloucester Rugby)*
Jack Clifford (Harlequins)
Luke Cowan-Dickie (Exeter Chiefs)
Max Crumpton (Saracens)
Ross Harrison (Sale Sharks)
Alec Hepburn (London Wasps)
Matt Kvesic (Worcester Warriors)*
George Merrick (Harlequins)
Nathan Morris (London Wasps)
Ben Nutley (Northampton Saints)
Kyle Sinckler (Harlequins)
David Sisi (London Irish)
Sam Twomey (Harlequins)*
Chris Walker (Leeds Carnegie)
Backs
Will Addison (Sale Sharks)
Josh Bassett (Bedford Blues)
Tommy Bell (Sale Sharks)
Jamie Elliott (Northampton Saints)
Tom Heathcote (Bath Rugby)
Sam Hill (Exeter Chiefs)
Ryan Mills (Gloucester Rugby)*
Ben Ransom (Saracens)*
Dan Robson (Gloucester Rugby)*
Henry Slade (Exeter Chiefs)
Ben Spencer (Saracens)
Charlie Walker (Harlequins)
Marland Yarde (London Irish)*
* Played in 2011 IRB Junior World Championship
IRB Junior World Championship schedule
Game 1
England v Italy
Monday, June 4th; 3:45 (GMT)
University of Western Cape Stadium, Cape Town
Game 2
England v Ireland
Friday, June 8th; 5:45pm (GMT)
Danie Craven Stadium, Stellenbosch
Game 3
South Africa v England
Tuesday, June 12th; 5:45pm (GMT)
Danie Craven Stadium, Stellenbosch
Semi-final
Sunday, June 17th
Final
Friday, June 22nd
