Scottish centre Sione Tuipulotu and Irish prop Finlay Bealham are both named in the starting lineup while Ireland wing Mack Hansen is among the replacements for Friday's contest, which will be the launchpad for the three-Test trip to take on the Wallabies.
It's a real boost for the three Australian-born players that they have been given first crack at playing in red for the Test side, which will be captained by England's Mario Itoje.
Itoje leads a starting XV that will feature English playmakers Marcus Smith at fullback, and Alex Mitchell and Fin Smith in the halves.
Coach Andy Farrell has put his faith in Scottish skipper Tuipulotu in a centre partnership with Ireland's Bundee Aki after the Melburnian returned from being injured for much of this season.
Canberra's Bealham has been pushed straight into the lineup after only being drafted in as a late addition to the squad last week because of Scot Zander Fagerson's injury withdrawal.
Hansen, one of Farrell's favourites when he was coaching Ireland, will get his chance to show off his mercurial skills from off the bench.
Hansen's compatriot Tadhg Furlong will be given the opportunity to prove his fitness after struggling with a calf injury that ruled him out of Leinster's United Rugby Championship final victory over the Bulls.
"Congratulations to Maro Itoje ahead of leading out the Lions for the first time. It's a truly special moment and one that very few players ever get to experience," Farrell said.
"Maro has led the group well during our time in Portugal and then Dublin this week. This is also our first opportunity to show what the 2025 Lions are about and what we want to stand for as a team."
The three Australian players will be among 14 players in all making their Lions debut against the Pumas.
Argentina have named a much-changed line-up with a first start for centre Justo Piccardo and three potential debutants off the bench.
Coach Felipe Contepomi has taken the opportunity to blood several new players in the matchday 23, though the side will be led by an old hand in hooker Julian Montoya.
Tomas Albornoz has been selected at flyhalf and forms the halfback pairing with Gonzalo Garcia, while Piccardo and Lucio Cinti are the centres.
British & Irish Lions team:
15 Marcus Smith (England), 14 Tommy Freeman (England), 13 Sione Tuipulotu (Scotland), 12 Bundee Aki (Ireland), 11 Duhan van der Merwe (Scotland), 10 Fin Smith (England), 9 Alex Mitchell (England); 1 Ellis Genge (England), 2 Luke Cowan-Dickie (England), 3 Finlay Bealham (Ireland), 4 Maro Itoje (England, capt), 5 Tadhg Beirne (Ireland), 6 Tom Curry (England), 7 Jac Morgan (Wales), 8 Ben Earl (England). Replacements: 16 Ronan Kelleher (Ireland), 17 Pierre Schoeman (Scotland), 18 Tadhg Furlong (Ireland), 19 Scott Cummings (Scotland), 20 Henry Pollock (England), 21 Tomos Williams (Wales), 22 Elliot Daly (England), 23 Mack Hansen (Ireland).
Argentina team:
15. Santiago Carreras, 14 Rodrigo Isgro, 13 Lucio Cinti, 12 Justo Piccardo, 11 Ignacio Mendy, 10 Tomas Albornoz, 9 Gonzalo Garcia; 1 Mayco Vivas, 2 Julian Montoya (capt), 3 Joel Sclavi, 4 Franco Molina, 5 Pedro Rubiolo, 6 Pablo Matera, 7 Juan Martín Gonzalez, 8 Joaquin Oviedo. Replacements: 16 Bautista Bernasconi, 17 Boris Wenger, 18 Francisco Coria Marchetti, 19 Santiago Grondona, 20 Joaquín Moro, 21 Simon Benitez Cruz, 22 Matias Moroni, 23 Santiago Cordero.
