The 94-times capped Charvis is the latest big name to commit himself to the match, which aims to raise £1m to provide practical support for those soldiers wounded in Afghanistan and Iraq, and he will line-up in Scott Gibbs’ International Select XV.
That will bring the current Dragons player-coach into direct conflict with Help For Heroes XV skipper Dallaglio at the home of English rugby.
The two players have played against each other for England and Wales no fewer than nine times down the years, with Dallaglio leading the contest 8-1.
“I know that Lawrence has the edge on Colin in the England v Wales games, but he might just remember the one win Colin was part of in 1999,” said Gibbs.
“We stole the game, and the Grand Slam, from England that day and I’m sure that defeat still hurts. It will be great having Colin at the heart of our pack because he is such a physical animal.
“I know he will relish one final chance to do battle with Lawrence and their contest should add some extra spark to what is shaping up to be a great game.”
Gibbs scored a mercurial try at Wembley back in 1999 when Wales triumphed 32-31 and is coming out of a four year retirement to lead the International Select XV.
He, and team manager Ieuan Evans, have already recruited former New Zealand wonder wing Jonah Lomu, Scottish stars Kenny Logan and Gordon Bulloch and Australian World Cup winner Jeremy Paul in a squad to play against a team that already contains Dallaglio, Will Greenwood and Austin Healey.
“The addition of Colin to the International Select XV shows this is going to be a highly competitive occasion. He is the first of a number of current Magners League players we hope to have in our squad,” said Evans.
“This game will give Colin the chance to put one over on Lawrence at Twickenham having failed to do so for Wales during his illustrious career.”
More than 20,000 tickets have already been sold for the Help For Heroes Challenge Match. Tickets are available for purchase from Ticketmaster by calling 0844 8472492 or on-line at www.ticketmaster.co.uk (£20 for adults and £10 for Under 16 – Family ticket at £50 for 2 + 2).
Charvis joins Help for Heroes match
Colin Charvis is set for one more tilt at arch-rival Lawrence Dallaglio when the two back row legends go head-to-head in the Help For Heroes Challenge match at Twickenham Stadium on 20 September.