Leicester Tigers flyhalf George Ford and Harlequins flanker Chris Robshaw will co-captain England in the match against the Barbarians for the Quilter Cup at Twickenham on Sunday, the Rugby Football Union (RFU) said on Friday.
Ben Youngs was also part of the squad named by England coach Eddie Jones for the uncapped fixture, with the Tigers scrumhalf making a return to action after shaking off a knee injury he picked up against Italy in this year's Six Nations tournament.
"This is a good young squad and their work ethic has been outstanding over the last two weeks," Jones said in a statement.
"Their application to learn has been very good but they are very young at test rugby level so this week's match against the Barbarians is a fantastic opportunity for them to step up.
"It is a great opportunity for them to show they deserve to wear the English rose, to show they can be in contention for the World Cup and a great opportunity for them to put us on the front foot ahead of the South Africa tour.
The team also included fullbacks Mike Brown from Harlequins and Elliot Daly from Wasps.
Sale Sharks' flanker Tom Curry, who became the youngest player to start an international for England in 90 years against Argentina last year, also found a place in the squad.
The Wasps duo of scrumhalf Dan Robson and flyhalf Danny Cipriani were named on the bench for the first time under Jones.
The three-match series in South Africa begins with the first test on June 9.
Squad: Elliot Daly, Jonny May, Henry Trinder, Piers Francis, Mike Brown, George Ford, Ben Youngs, Joe Marler, Jack Singleton, Kyle Sinckler, Elliott Stooke, Joe Launchbury, Chris Robshaw, Tom Curry, Zach Mercer.
Replacements: George McGuigan, Ellis Genge, Nick Schonert, Josh Beaumont, Mark Wilson, Dan Robson, Danny Cipriani, Denny Solomona.