The Tigers pair join teammate Ben Youngs in the 26-man group for this summer’s tournament in Japan.
Cobden and Hurrell replace injured centre Tom Casson (Saracens) and wing Seb Stegmann (Harlequins).
Mark Mapletoft, England Under-20 coach, said: “It’s always a shame when you lose players to injury but in Will and Jack we have two high-quality replacements who have a great chance to make a mark on the world stage.
“Will’s been involved with us throughout this season, while Jack has been good form for Nottingham on the wing and in the centre, as well as playing at full back for Leicester’s A team, so he gives us extra flexibility.”
Both players joined the squad for last week's six-day training camp at Loughborough and will fly to Tokyo on May 27.
England start the tournament with Pool B games against hosts Japan on June 5 (7pm), Scotland on June 9 (5pm) and Samoa on June 13 (1pm), all at the Prince Chichibu Stadium in Tokyo. The semi-finals and finals are scheduled for June 17 and June 21.
England Under-20 Junior World Championship Squad
Forwards
Bob Baker (London Wasps)
Calum Clark (Leeds Carnegie)
James Clark (London Irish)
Carl Fearns (Sale Sharks)
James Gaskell (Sale Sharks)
Jamie George (Saracens)
Graham Kitchener (Worcester Warriors)
Shaun Knight (Gloucester Rugby)
Courtney Lawes (Northampton Saints)
Joe Marler (Harlequins)
Ben Moon (Exeter Chiefs)
Josh Ovens (Bath Rugby)
Dan Williams (Gloucester Rugby)
Chris York (Harlequins)
Backs
Rory Clegg (Newcastle Falcons)
Jack Cobden (Leicester Tigers)
Luke Eves (Bristol Rugby)
Tom Homer London Irish)
Will Hurrell (Leicester Tigers)
Dave Lewis (Gloucester Rugby)
George Lowe (Harlequins)
Rob Miller (Newcastle Falcons)
Charlie Sharples (Gloucester Rugby)
Henry Trinder (Gloucester Rugby)
Greig Tonks (Leicester Tigers)
Ben Youngs (Leicester Tigers)
