Gravell and fellow flanker Gavin Lucas (29) are the most experienced members of a pack that includes six players under the age of 25. The front row of Rhys Gill, Ross Johnston and Scott Roberts have shone in the earlier cup rounds that included away victories at Neath and Swansea and then a narrow win over Bridgend in the semi-final at Sardis Road.
At 22, Roberts is the oldest of the trio and he will fly back from Friday night replacement duty with Cardiff Blues in Scotland in anticipation of a second cup medal in as many years. Last season he was a member of the Pontypridd team that beat Neath in the final.
The youngest member of the pack is 19-year-old lock James Down while second row partner Chris Stamatakis is one of three in the starting line-up with over 100 games for the club.
Elgan Jones is set to play his 130th game for the Blue and Blacks followed by Stamatakis (114) and Leon Andrews (102) while Richard Jones looks forward to making his 99th appearance.
Saturday's cup tie will be Cardiff's 155th since 1972, their first final since 1997 and their eleventh in all, having won seven of the previous ten.
It will also be their third cup meeting with Llandovery. In previous encounters they beat the Drovers 40-22 at Church Bank in January 1999 and 10-0 in a quarter-final at the Cardiff Arms Park last season.
Cardiff: Jamie Roberts; Elgan Jones, Richard Davies, Richard Jones, Leon Andrews; Craig Evans, Tom Isaacs; Rhys Gill, Ross Johnston, Scott Roberts, Chris Stamatakis, James Down, Gavin Lucas, Adam Powell, Gareth Gravell (Capt)
Replacements: Ryan Price, Gareth Gunter, Alex Murphy, Matthew Amos, Nick Hampson, Darren Allinson, Leigh Halfpenny
Referee: Hugh Watkins (Cadoxton, Neath)