'The Pack' will be made up of 6,000 volunteers across the tournament, with 75% of the volunteers being recruited directly from rugby clubs in England and Wales.
Volunteers will play a key role in the delivery of the six-week tournament with a range of roles including transport, meet and greet, accreditation and way-finding which will all vary in duration.
Recruitment will begin on March 17 through an online application process when WRU and RFU clubs will nominate between one and two of their members to join 'The Pack' and take part in selection events ('Try Outs') across England and in Cardiff throughout 2014.
The WRU is delighted to work in conjunction with England Rugby 2015 to issue an exclusive invite to Welsh rugby volunteers to join in the Rugby World Cup celebrations in Cardiff.
"This is a great opportunity for the excellent rugby volunteers in Wales to get close to the action when eight Rugby World Cup games are played at the Millennium Stadium in 2015," said WRU Group Chief Executive Roger Lewis.
"There's a fantastic tradition of volunteering throughout the rugby clubs in Wales and it's great that those working hard behind-the-scenes at our local rugby clubs will be rewarded with the chance to take part in the greatest rugby tournament in the world."
The application process will be open for one month between March 17 and April 17, followed by 'Try Outs' from June-December, with successful members of 'The Pack' confirmed in early 2015.
In addition, 'The Pack' will bring 1,500 potential new volunteers into rugby through a national campaign, with the aim of retaining them beyond 2015 as part the tournament's legacy.
Members of the general public can register their interest in joining 'The Pack' from today at www.Rugbyworldcup.com/volunteers and details will be sent directly to all those signed up to The Front Row - the official newsletter for Rugby World Cup 2015 (www.Rugbyworldcup.com/frontrow).
Chief Executive of the England 2015 Organising Committee, Debbie Jevans, said: "'The Pack' will play a big role in the delivery of Rugby World Cup 2015, welcoming the world to England, Cardiff, and to the game of rugby. True to our vision, rugby is at the heart of our volunteer programme and we will recruit 75% of the 6,000 volunteer members of the 'The Pack' from rugby clubs in England and Wales, working with the RFU and WRU. This is a great opportunity to recognise those who support the game week in week out in their club and community.
"In addition we want to bring new people into rugby and will run a national campaign searching for 1,500 volunteers to join 'The Pack' with the aim of keeping them involved in the game beyond 2015.
"Members of 'The Pack' will help us to provide the teams and fans with a fantastic experience in 2015 and we look forward to opening the application process in March."