Llanelli RFC is hosting a live extract of 'Grav' at the pitchside in Parc y Scarlets ahead of its first performance in Milford Haven next month.
Gravell played for Llanelli from 1970 until 1985 and was president of the club until his death in 2007.
He was capped for Wales and the British Lions, and worked on screen and radio.
Gravell was part of the 1972 Llanelli side that beat the touring All Blacks 9-3 at Stradey Park.
He played for his country 23 times and was considered one of the great centres.
After retiring from rugby he went on to appear in a number of film and television productions including Rebecca's Daughters alongside Peter O'Toole, and was a much-loved rugby commentator for the BBC and Welsh language channel S4C.
He died in 2007 following complications from diabetes.
Welsh actor Gareth John Bale, who helped devise the show along with Torch Theatre director Peter Doran, will take the role of Grav.
A one-man show depicting the life and times of rugby legend and broadcaster Ray Gravell is having a launch at the club to which he dedicated his life.