Harlequins flanker Alex Dombrandt will start for an inexperienced England XV against the Barbarians on Sunday.
The university graduate, 22, only made his senior debut earlier this season.
England women also play the Barbarians in a historic double-header at Twickenham, with Grand-Slam winning captain Sarah Hunter leading the Red Roses.
Sale forward Josh Beaumont captains the men's side from the second row while Quins' Marcus Smith starts at fly-half.
Northampton's Teimana Harrison is the only full England international to start the non-cap match.
"Alex Dombrandt understands the game and he's still developing his body into a proper Premiership and hopefully international rugby player," England scrum-half Danny Care said on the Rugby Union Weekly podcast.
"Playing the Barbarians at Twickenham in an England shirt - he's said it's a dream come true for him."
Although none of these players are expected to be part of Eddie Jones' World Cup plans at this stage, the England XV coach Jim Mallinder says they have a big chance to impress against a stellar Barbarians line-up.
"This game will be massive for them and you can see their motivation and desire," he said. "They all have really deserved the opportunity this weekend."
Marler in, Cipriani out
Barbarians coach Pat Lam had wanted to include Premiership player of the season Danny Cipriani in his squad, but the Gloucester fly-half was unavailable. Lam took this to mean that Cipriani might be included in England head coach Eddie Jones' World Cup squad.
"I spoke with Danny but he wasn't available. I'm predicting that the players who weren't available - and this isn't guaranteed - will be in their World Cup squads," Lam said.
The former New Zealand international has called up Harlequins prop Joe Marler, who retired from international rugby last year.
Marler has suggested he would return for the World Cup if England desperately needed him. Prop Mako Vunipola has sustained a hamstring injury, but Eddie Jones has other options in Ellis Genge, Ben Moon and Alec Hepburn.
"If they needed me to go out there and help them out, I'd have the conversation with my wife and think about it and say 'yeah all right, I'll help you out'," Marler said.
"If it was an SOS scenario it would definitely be something I'd consider, but they're not in an SOS scenario.
"If they were desperate I would give them a hand, but they're not, so, I'm happy where I'm at. I look forward to watching it as a fan and hopefully they go well."
The Barbarians are an invitational team which has been playing national sides on a regular basis since 1948.
Historic day for Barbarians women
The Barbarians women began life with wins over Munster and the British Army in 2017-18 but only played their first international in April 2019.
This will be the first time England women have faced the side, but injuries have left head coach Simon Middleton without a number of Grand Slam winners.
Bristol Bears hooker Clara Nielson and Harlequin Ladies prop Chloe Edwards could make their first England appearance off the bench.
There is no shortage of experience in a Barbarians side which includes Rochelle Clark, Danielle Waterman and Tamara Taylor, who were World Cup winners with England in 2014, along with Welsh pair Jasmine Joyce and Elinor Snowsill and Ireland's Claire Molloy.
The women's game kicks off at 12:45 BST, followed by the men's game at 15:30.
Highlights will be on BBC Two at 23:30 BST on Sunday.
Line-ups
England women: McKenna; Thompson, Tuima, Reed, Smith; Harrison, Riley; Botterman, Davies, Bern, Aldcroft, Scott, Cleall, Brown, Hunter.
Replacements: Nielson, Perry, Edwards, Galligan, Burnfield, Hunt, Heard, Williams.
Barabarians women: Waterman; Joyce, Wood, Naoupu, Derk; Snowsill, Sue; Clark, Fa'amausili, Ta Ohaere-Fox, Farmer, Dennison, Lavea, Molloy, Itunu.
Replacements: Kerr, Keates, Mignot, Taylor, Gulliver, Casey, Large, Ahki.
England men: Hammersley; O'Conor, Marchant, Williams, Bassett; Smith, Mitchell; Harrison, Dunn, Painter, Stooke, Beaumont, Dombrandt, Curry, Harrison.
Replacements: Taylor, Obano, Hill, Spencer, Ellis, White, Sheedy, Loader.
Barbarians men: Piutau; Adeolokun, Fekitoa, Atkinson, Naiyaravoro; Slade, Webb; Marler, Hibbard, Afoa, Horwill, Vui, Luatua, Louw, Mata.
Replacements: Heffernan, Schoeman, Bealham, Isa, Messam, Williams, James, Nakosi.