Welford Road is the setting for Tigers v the Ospreys (kick-off 7.45pm) in a repeat of the 2007 and 2008 Anglo-Welsh cup finals.
And Williams, who made his professional debut in the competition for the Scarlets, is set to face some old friends.
“I could be playing against some of my mates,” Williams tells tonight’s matchday programme.
“Growing up I played with Matthew Morgan, Tom Habberfield, Ross Jones and Dan Baker the No8 who has just won a Welsh cap in the summer. It’s going to be strange!”
Tigers have named a youthful squad for the game with Javiah Pohe and George Catchpole making their debuts at centre. Miles Benjamin, Joe Cain and Harry Thacker make their first starts at Welford Road, while on the bench, Tiziano Pasquali and Perry Humphreys could make their first-team bows.
Williams says: “It’s great for youngsters to get an opportunity. Javiah (Pohe) and Catchy (George Catchpole) two young centres are making their first starts for the club. It’s going to be great for them.”
Read more from Williams in tonight’s matchday programme and you can also hear from Tom Price, Henry Purdy and Harry Wells on their victorious Junior World Championship campaign with England U20s.
The programme is available around the ground priced £3.