As a result, the game will have a later than normal kick-off time of 3.00pm.
The clash between the last two teams to win the Welsh Premier League will see the Saints up against their former midfielder John Leah.
The Huws Gray Alliance Lillies shocked big-spenders Neath at The Gnoll in the previous round with a penalty shoot-out victory.
This Saturday's away Welsh Premier fixture at Aberystwyth is also live on S4C (3.45pm kick-off) as is the Loosemores League Cup final between TNS and Llanelli, also at Park Avenue (3.00pm kick-off).
Meanwhile, the thrice-postponed league fixture at home to Llanelli has now been re-arranged for Tuesday February 8 (7.45pm) at Park Hall.
Remaining fixtures before the mid-season split:
Sat 8 Jan Aberystwyth Town (A) League
Wed 12 Jan Carmarthen Town (A) League
Sat 15 Jan Haverfordwest County (A) League
Tue 18 Jan Bangor City (H) League
Sat 22 Jan Llanelli AFC (Park Avenue) League Cup
Sat 29 Jan Rhyl FC (A) Welsh Cup
Sat 5 Feb Newtown AFC (A) League
Tue 8 Feb Llanelli AFC (H) League
Photo: A late goal from Chris Sharp gave the Saints a 2-1 win on their last visit to Belle Vue.