BILLY Twelvetrees is the fourth replacement to join the British and Irish Lions on their tour of Australia.

The versatile England back left his country’s tour of Argentina in Buenos Aires today to answer the call.

The 24-year-old Gloucester player can play at both centre and outside half.

He will join the Lions in Sydney with injury concerns over fly-halves Owen Farrell (dead leg) and Jonathan Sexton (hamstring).

And there are also questions marks over centre Manu Tuilagi who suffered a stinger in last Saturday’s 22-12 victory over Queensland Reds in Brisbane.

Twelvetrees won his fifth England cap in last weekend’s 32-3 victory over Los Pumas in Salta, scoring a try in an impressive individual performance.

The three other late arrivals for the Lions on their tour Down Under are loosehead props Alex Corbisiero and Ryan Grant and the Ireland wing Simon Zebo.

Twelvetrees had been due to start in his country’s second Test in the Argentine capital on Saturday.

England coach Stuart Lancaster said he and his squad were all pleased for the ex-Bedford and Leicester man.

“All the England players and management are delighted for Billy to get this great opportunity,” he said.

“He’s played well for England this year, underlined that form with his display against Argentina at the weekend and goes with our full support and blessing.”

Twelvetrees has not been called up as cover for any one player, but to give head coach Warren Gatland additional options and ease the work-load on the fit members of the back division.

The Lions play the New South Wales Waratahs on Saturday and the Brumbies next Tuesday before the first Test against Australia.

Gatland said: “The nature of a Lions tour means that there will inevitably be knocks.

“The whole squad have worked hard but a lot of the backs have doubled up over the last two games, either starting or from the bench.

“Billy played well in the first Test for England and he provides that versatility to cover a variety of positions.”

The Lions play the Wallabies in a three-match series with Tests on June 22, 29 and July 6, having lost the last one 2-1 in 2001 after leading 1-0 in an epic battle.