England star Twelvetrees flies out to bolster the Lions

The 24-year-old, who can play at centre and fly-half, has left Buenos Aires for Australia.

The Lions have injury concerns over fly-halves Owen Farrell (dead leg) and Jonathan Sexton (hamstring), while centre Manu Tuilagi suffered a stinger in the victory over Queensland Reds.

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

The Gloucester player will be the fourth player to be called up by the Lions following the late arrivals on tour of loose-head props Alex Corbisiero and Ryan Grant and the Ireland wing Simon Zebo.

Twelvetrees had been due to start England’s second Test against Argentina on Saturday.

England coach Stuart Lancaster will name his team today, with Bath’s Kyle Eastmond likely to step into the inside centre role to make his first Test start.

Twelvetrees is the second England player to be summoned to Australia from the tour of Argentina, following Corbisiero, who received the call-up last Wednesday.

Lancaster said: “All the England players and management are delighted for Billy to get this great opportunity.

“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 ACT Brumbies next Tuesday before the first Test against Australia.

Gatland said: “The nature of a Lions tour means that there will inevitably be knocks which take time to recover from.

“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.”

Sean O’Brien anticipates his former Leinster coach Michael Cheika sending out a fired-up New South Wales Waratahs team against the Lions on Saturday.

It promises to be tough challenge for Cheika, given that he is without 10 players currently in the Australia camp preparing for next week’s first Test and a further six on the injured list.

But Lions flanker O’Brien said: “I know ‘Cheiks’ very well with him being at Leinster. He is an animated character as well, so I am sure he will have them fired up and wanting to be really aggressive and come hard at us.”