Bombardier Bethan Dainton will become the first female military rugby union player to feature for Barbarians this weekend.
The famous invitational side play South Africa at Twickenham Stadium.
The Army were the first team to play against the Barbarians Women's team after their creation in 2018.
"I didn't quite believe it if I'm honest," said Bdr Dainton.
"I didn't expect it – it's like the pinnacle of your career and it's not something you get offered often.
"So, I couldn't actually say no."