They will be joined by England flanker Steffon Armitage (Pau), Samoa lock Joe Tekori and France centre Yann David (both Toulouse).

The latest call-ups take the number of players at Scotland boss Cotter’s disposal to 15 with more invitations to follow, particularly for the key fly half role.

Scrum half Pienaar and full back Piutau have enjoyed outstanding campaigns for Ulster, both featuring in the Pro 12 Dream Team with Piutau picking up the Pro 12 Guinness Players Player of the Year award.

Pienaar’s appearance against the Barbarians will be the last of his seven-year spell in Belfast.

Both players have featured for the Barbarians before. Pienaar made the last of his five appearances in the win over Fiji in Belfast last November while Piutau scored on his only previous appearance, also against Fiji, in 2013.

David, Pienaar and Piutau pair join a back division alongside Australia’s Will Genia and Adam Ashley-Cooper, France’s Maxime Medard and Connacht’s uncapped Bundee Aki.

Ruan Pienaar in action against Fiji at the Kingspan Stadium in 2016

Armitage and Tekori are part of a powerful forward group with experienced internationals from five different countries that also includes Argentina’s Patricio Albacete and Facundo Isa, New Zealand’s Corey Flynn and Jeremy Thrush and France great Thierry Dusautoir.

The Barbarians will face England for the 16th time since 1990 this month, having won seven and lost eight in the overall series. Their mach against Ulster is the first time the sides have met since 1957 but the club enjoyed a successful visit to Belfast last year when they beat Fiji 40-7.

Tickets for the Old Mutual Wealth Cup – England v Barbarians – are available now from £5 for kids and £25 for adults. Visit www.englandrugby.com/tickets