Shane Williams has revealed his sense of shock after being summoned from Japan to play for the British and Irish Lions.

The 36-year-old former Wales wing, who retired from Test rugby 18 months ago, will line up against the Brumbies in Canberra tomorrow.

He is joined in the three-quarter line by two England backs, wing Christian Wade and Brad Barritt, who had yet to arrive in Australia from Argentina and the United States respectively yesterday, while centre Billy Twelvetrees only touched down three days ago.

Lions head coach Warren Gatland’s team for the Brumbies clash features six players – Wade, Barritt, Twelvetrees, Williams, prop Ryan Grant and hooker Rory Best – who were not original selections among his 37-man tour squad.

Williams, a Lion in 2005 and 2009, is due to be a radio summariser for the three-Test series against Australia.

But he now finds himself pulling on the famous red shirt once again as the Lions grapple with injury concerns – notably Wales backs George North and Jamie Roberts – and giving players sufficient recovery time before next Saturday’s series opener.

“I had a phone call to see whether I would be able to help them out because there are a couple of injuries in the squad,” Williams told talkSPORT.

“There was no chance I was going to say no, to be honest with you.

“It was completely out of the blue.

“I never thought I would ever get this opportunity again, but if me contributing on Tuesday is going to help the Lions squad be successful in the three Tests then that is what I am here to do.

“I am here to provide any help they need to be successful in the Test series.”

Williams, who currently plays for Mitsubishi Dynaboars in Japan, will train with the Lions today, play tomorrow and then leave the squad on Wednesday.