Their shirts, along with the other 20 Barbarians who featured in the MasterCard Trophy match against England at Twickenham on May 30, are being auctioned on eBay to raise funds for the RFU's Injured Players Foundation.
Kay made his final appearance at Twickenham in that game before announcing his retirement to move behind the microphone with ESPN, while for prop White the match represented a first-ever appearance for the invitational Barbarians side.
The auction for the 22 jerseys, each one individually signed, is now open and bidding for these unique items is expected to be fierce.
All the proceeds will be donated to the IPF, a charity which supports people who sustain a catastrophic injury while playing rugby union in England.
The Baa-Baas: Paul Warwick (Munster), Paul Sackey (London Wasps & England), Casey Laulala (Cardiff Blues), Florian Fritz (Toulouse & France), Cédric Heymans (Toulouse & France), Jean-Baptiste Elissalde (Toulouse & France), Byron Kelleher (Toulouse & New Zealand), Rodrigo Roncero (Stade Francais & Argentina), Benoit August (Biarritz & France), Julian White (Leicester Tigers & England), Ross Skeate (Toulon), Ben Kay (Leicester Tigers & England), Rodney So'oialo (Hurricanes & New Zealand), Martyn Williams (Cardiff Blues & Wales), Xavier Rush (Cardiff Blues & New Zealand). Reps: Ken Owens (Scarlets), Census Johnston (Toulouse & Samoa), Jérome Thiôn (Biarritz & France), George Smith (ACT Brumbies & Australia), Pierre Mignoni (Toulon & France), Fabrice Estebanez (Brive), David Smith (Hurricanes)
For more information or to join the auction, click here.