Scarlets and Ospreys will lock horns in the RaboDirect Pro 12 on Boxing Day with Adam Jones set for his 150th appearance for the visitors.
Watch the RaboDirect Pro 12 Rugby on BBC Wales on Monday, December 26 at 1405 GMT.
The Scarlets are seventh on the ladder with 22 points after four wins and one draw this season, while Ospreys are second on the ladder and they will be looking to go top of the tree if they pick up their ninth win of the season and Leinster fail to beat Ulster.
The home team welcome back Wales winger George North after recovering from a dead leg he suffered on international duty.
Second row Damian Welch is missing with a fractured thumb, although Rhys Priestland will start at number 10 with Gareth Davies partnering him in the halves.
Ospreys director of coaching Scott Johnson is not taking this match lightly despite the gulf in class on the ladder.
He said: “There's always a lot of pride at stake in these derby fixtures, on and off the pitch, and it's not going to be any different on Monday.
"You've got two teams who will be stinging a little bit after the disappointment of the last two weeks in Europe, but what I can guarantee you is that we are itching to get back into it and want to make the fans proud of this team in a big game that will have all the intensity of Europe.
Scarlets can be backed at 4/7 to take the festive points, while Ospreys are on offer at 11/8 with the draw available at 22/1.
This should be a tight affair and the hosts can be backed at 11/5 with
Paddy Power to win by 1-7 points, while Ospreys are on offer at 16/1 to take the game by 15 or more points.
