Lachlan Coote has become the second Australia-born player to be called up by Great Britain coach Wayne Bennett.
Coote, who has British ancestry and played for Scotland in the 2016 Four Nations Series, joins Warrington stand-off Blake Austin in a 29-strong performance squad to prepare for the end-of-season tour to New Zealand and Papua New Guinea.
Coote's Saints team-mate Morgan Knowles, who played for Wales in the 2017 Rugby League World Cup, is also one of five new faces but winger Regan Grace, his team-mate for club and country, is not among them.
Instead Bennett has called up Leeds Rhinos winger Ash Handley, the leading try-scorer in Super League in 2019.
"As we've said since the return of the Great Britain team was announced at the start of the year, we have considered everyone who is eligible and puts themselves forward," Bennett said.
"As well as this performance squad of players based in England and France, we've got another group of players based in the NRL to consider - and there's still time for others who are eligible to impress and force their way in."
The other newcomers are Warrington Wolves forward Joe Philbin, who played for Ireland at the last World Cup, and Salford Red Devils second rower Josh Jones. St Helens forward Matty Lees would have been a sixth fresh face but for injury.
Also ruled out through injury are Wakefield winger Tom Johnstone and Castleford half-back Luke Gale while Warrington second rower Ben Currie was left out to allow him to have a full off-season after his recent injury problems.
The squad will meet for the first time in Leeds next Tuesday to begin the preparations for the first Lions tour since 2006. Training will start during the Super League play-off series in early October.
The squad is expected to be captained by Wigan and England skipper Sean O'Loughlin, who is set to return from a pectoral injury before the end of the domestic season.
He and St Helens hooker James Roby are the only players in the Super League-based squad to have represented Great Britain in the past.
The squad was selected by a seven-man panel which also included assistant coaches Ian Watson and Danny Ward, team manager Jamie Peacock and three more former Lions tourists in Paul Anderson, Paul Sculthorpe and Paul Wellens.
The final 24-man squad will be announced within 48 hours of the Grand Final on October 12. The Lions' first match will be against Tonga in Hamilton on Saturday, October 26.
Great Britan elite performance squad: Jake Trueman, Liam Watts (both Castleford), Sam Tomkins (Catalans Dragons), Jermaine McGillvary (Huddersfield), Jake Connor, Jamie Shaul, Scott Taylor (all Hull FC), Ash Handley, Stevie Ward (both Leeds), Jonny Lomax, Tommy Makinson, Mark Percival, J Roby, Luke Thompson, Alex Walmsley, Morgan Knowles, Lachlan Coote (all St Helens), Josh Jones (Salford), Reece Lyne (Wakefield), Blake Austin, Josh Charnley, Daryl Clark, Chris Hill, Jack Hughes, Joe Philbin, Stefan Ratchford (all Warrington), Oliver Gildart, Sean O'Loughlin, George Williams (all Wigan)