Johnson's last game of rugby was his testimonial in June 2005

England manager Martin Johnson is to come out of retirement to play in a one-off charity match at Twickenham.

Johnson will play in the Help for Heroes match on 20 September alongside World Cup-winning colleague Lawrence Dallaglio, who will lead the Heroes XV.

The game will aim to raise �1m for the care of British service personnel injured in Iraq and Afghanistan.

It will be Johnson's first competitive game since his testimonial farewell against a Jonah Lomu XV in June 2005.

"I've kept myself fit and although I've appeared in some one-off charity rugby and football matches this will be the first - and I'm sure last - time that I'll play in a competitive match against some world class players," Johnson said.

"As soon as I was asked to play by Lawrence Dallaglio, I didn't hesitate to say yes."

It will be the first time Johnson and Dallaglio have played together since the 2003 World Cup final.

Dallaglio retired after leading Wasps to victory in the Guinness Premiership final over Leicester on 31 May this year.

The Heroes side, managed by another former England captain, Phil de Glanville, will face an International XV overseen by Ieuan Evans and led by Johnson and Dallaglio's former Lions team-mate Scott Gibbs.