It sets up a repeat of the 2012 final between Cross Keys and Pontypridd, and Gregg Woods' men will be hoping for a similar result after they upset the odds to win 32-19 two seasons ago.
Ponty thumped Aberavon 32-3 at the Brewery field to secure their place in the final, keeping their hopes of a historic treble alive.
The final will be played on May 4, when Prangell is hoping Cross Keys' passionate supporters can once again roar their team on to victory.
"The fans have been fantastic," said Prangell. "We've had more support than ever in this campaign, and I'm getting plenty of pats on the back from people in the local paper shop!
"We have had more support than ever. It has kicked on since we reached the final of the British & Irish Cup and they've been great ever since."
Tries from James Cordy-Redden, captain Leon Andrews and replacement wing Elliot Jones, along with fourteen points from the boot of Dorian Jones, led the Pandy Park outfit to victory over The Drovers.
Prangell was relieved to setup a return to the hallowed Millennium Stadium turf after a stunning semi-final encounter, and he says all the pressure is on Swalec Cup holders Ponty.
"I'm just glad to be going back to the Millennium Stadium. It was such a tight game against Llandovery and it went right to the wire," added Prangell.
"Some of our boys have played at the stadium before but it will be a great opportunity for the young lads to experience a big game there.
"Gregg Woods, Morgan Stoddart and Jevon Groves have done a great job coaching the boys and have had a real influence on their success.
"We love the tag of being underdogs, and we believe we can beat anyone in the league, that's what makes the Principality Premiership and Swalec Cup such great tournaments.
"It will be the two best clubs in the division going up against each other in the final. Ponty are like the fifth region, they're the Manchester City of the Premiership as they have such good players and are able to recall players who are playing rugby at the highest level, as they did with their captain Chris Dicomidis in their semi-final."