Andre Esterhuizen has provisionally signed up for the Barbarians’ clash with a World XV at Twickenham in May.
The South Africa centre will look to drive Harlequins to the Gallagher Premiership final on May 27.
But if Quins do not make the league showpiece, Esterhuizen will claim a significant consolation prize of turning out for the world-famous BaaBaas the following day, on May 28.
Powerhouse centre Esterhuizen has been joined among the growing Barbarians ranks by gifted former New Zealand playmaker Aaron Cruden.
The 34-year-old won 50 All Blacks caps between 2010 and 2017, and has been plying his trade in Japan in the last few years.
“Andre Esterhuizen has been a major threat for Harlequins in the last few years and will offer huge power to the Barbarians’ backline,” said a source close to the Barbarians.
“Of course his first priority is rightly trying to push Quins all the way in the Premiership, but we’d like to think we can offer a pretty decent back-up option!
“Aaron Cruden will be a hugely exciting foil to the likes of Andre with his creative talents, in what’s already shaping up to be an extremely high-quality squad.”
Eddie Jones will coach the Barbarians, and has reconfirmed his commitment despite being appointed as Australia’s new boss.
The former England chief will pit his wits against long-time coaching rival Steve Hansen, with the ex-All Blacks supremo taking charge of the World XV.
The two decorated coaches have both been trying to convince Bristol’s star centre Semi Radradra to join their ranks. But the Fiji powerhouse is now likely to opt for Hansen’s World XV.
Hansen is also expected to be able to call on Australia backs Marika Koroibete and Nick Phipps, as well as the All Blacks’ Ngani Laumape.
The Barbarians meanwhile will also be able to call on Wales great Alun Wyn Jones, who has committed to Jones’ cause.
London Irish's Australia lock Rob Simmons is another on the Barbarians' roster, alongside Leicester's England prop Dan Cole.
Tickets for the Barbarians vs World XV at Twickenham on Sunday, May 28 are on sale now. Log on to www.ticketmaster.co.uk/barbarians for more information