Lawrence Dallaglio, who last Saturday led London Wasps to the Guinness Premiership title at Twickenham, will return to the stadium in September as the best-known face in rugby's support for servicemen wounded in Afghanistan and Iraq.

Dallaglio, who retired from the sport after 18 years in the colours of Wasps, England and the British Lions, has been designated the non-playing captain of a Help for Heroes XV, but he has not ruled out taking the field himself against an international selection in a match, which aims to raise £1million.

The RFU will provide the stadium and its administrative expertise without charge to help an event that is the brainchild of Mark Souster, rugby writer with The Times. Souster, moved by the efforts of servicemen and women and the need to help those injured in the line of duty, has gathered support from leading figures in the game, from former players, from Gordon Brown, the Prime Minister, and from the deputy chairman of the Conservative party, Lord Ashcroft, who owns the largest collection - more than 140 - of the highest award for conspicuous bravery, the Victoria Cross.

The specific aim of the charity, Help for Heroes, begun last October by Bryn Parry, the cartoonist and himself a former serviceman, is to raise £9million to complete the refurbishment of the swimming pool at Headley Court, Leatherhead, where service personnel injured on duty receive treatment. Hydrotherapy is a vital component for the men and women whose lives have been changed by the wounds received in battle and whose fight to recover some normality in their daily lives is a never-ending struggle.

Neither Dallaglio nor Scott Gibbs, the former Wales centre who was his playing colleague on the 1997 Lions tour in South Africa, had any hesitation in accepting leadership of the respective XVs for a match on September 20, which the organisers believe will fill Twickenham to its 82,000 capacity. Given that the annual Army-Royal Navy match last month drew more than 50,000, it is a realistic ambition, despite the rival attractions over the weekend of Premiership and Magners League matches, not to mention the Ryder Cup golf tournament and tennis's Davis Cup.

Dallaglio understands how sport has helped servicemen endure the abnormality of war, from the numerous faxes and e-mails which flood in from overseas, not least last week during the build-up to the Premiership final against Leicester. “The chance to watch a rugby or football match gives them relief from what is such a difficult job,” he said.

“There are things in life more important than rugby and support for this cause is one of them. Like millions of people all over the country, I'm proud of the efforts of our servicemen and women and they put sport into context. The reality of war is that people's lives change forever and this will help provide much-needed funds for something very serious, very important - and rugby will do it in the right way. It has to be competitive and it has to be well-run.”

The two sides, who will be kitted out by Nike, will be managed by two more former international captains, Phil de Glanville, of England, and Ieuan Evans, of Wales, and have already attracted the sponsorship of Investec, the insurance company. The RFU are seeking eight sponsors each willing to contribute £60,000 to cover expenses so that every element of the gate receipts can go to the rehabilitation centre.

The two teams will be composed of international players, developing players such as those from the representative under-20 sides, and players from the three armed services. It is hoped they will be coached by RFU staff such as the former internationals, Nigel Redman and Jon Callard, and Dallaglio has already threatened to contact his colleagues in England's legendary back row, Richard Hill and Neil Back, to make a contribution to the day.

Negotiations are well advanced with a broadcaster and it is possible that the Premiership fixtures for that weekend could be spread between Friday and Sunday, so as to leave the Saturday as clear as possible for leading players to attend and help raise the profile of the occasion.

Premiership directors of rugby and Premier Rugby Ltd, the umbrella body, have indicated their support. “There is an appetite for this sort of game and I believe players will be queuing up to offer their services,” Dallaglio said.