Purdy, who played in the Under-20s Six Nations this season and made his Tigers senior debut in the LV= Cup, has been added to the squad after Sale Sharks centre Mark Jennings was ruled out with an arm injury.
He joins club colleague Harry Wells and Tom Price in the England squad.
England Under 20 IRB Junior World Championship squad
Forwards
Dom Barrow (Leeds Carnegie)
Jack Clifford (Harlequins)
Joel Conlon (Exeter Chiefs)
Luke Cowan-Dickie (Exeter Chiefs)
Matt Hankin (Saracens)
Alec Hepburn (London Wasps)
Danny Hobbs-Awoyemi (Northampton Saints)
Ross Moriarty (Gloucester Rugby)
Nathan Morris (London Wasps)
Tom Price (Leicester Tigers)
David Sisi (London Irish)
Tom Smallbone (London Irish)
Scott Spurling (Saracens)
Elliott Stooke (Gloucester Rugby)
Harry Wells (Leicester Tigers)
Scott Wilson (Newcastle Falcons)
Backs
Callum Braley (Bristol Rugby)
Alex Day (Northampton Saints)
Ollie Devoto (Bath Rugby)
Sam Hill (Exeter Chiefs)
Will Hooley (Northampton Saints)
Ben Howard (Worcester Warriors)
Jack Nowell (Exeter Chiefs)
Henry Purdy (Leicester Tigers)
Henry Slade (Exeter Chiefs)
Harry Sloan (Harlequins)
Tom Stephenson (Northampton Saints)
Anthony Watson (London Irish)
