Excitement has been building as the Bell Close club prepare to play the Southern League Division One Central champions.
And while their opponents, who have just secured promotion from Step 4, start as favourites, Leighton are determined to give it their best shot.
"We start as massive underdogs,” said manager Lee Bircham. “Everyone knows that. But we’re not just there to make up the numbers, we are going there to win it.
"It’s great to be in the final against what’s effectively now a Step 3 team. It will be good to see how we play against them being at full strength. It should be a good test and we’re looking forward to it.
"Bedford have won their league, so there will be a party atmosphere for both sides as both clubs are very well supported and they’re going for the league and cup double.”
Bircham hopes Leighton’s huge following of fans will be behind them.
"I’d like to thank the Leighton supporters, who so far have been absolutely outstanding,” he added. "They are our 12th man and such an important part of the club.”
The cup final is all ticket, with details on the club website.
Leighton finished their Spartan South Midlands League Premier Division fixtures on Saturday with trip to Hadley, going down 3-0 to finish the campaign on 71 points from their 38 games.
"We hadn’t been beaten so far, so although it wasn’t a good performance, it was good for me to see the players when things aren’t going their way,” said Bircham.
"It’s good to see their reaction and also the reason why Hadley are third and look like being promoted and we are fourth.”
New Salamis beat Risborough Rangers in the title decider last weekend, to be promoted as champions. But it appears runners-up Rangers won’t gain promotion due to ground grading issues.
Bircham knows how much his side need to improve for next season.
"We definitely need to be better,” he added. "The players have had three managers this season and an interim, which must have been unsettling, but we know we need to improve for next year.”