Liverpool boss Jurgen Klopp says it'll be good to see Alex Mac Allister face brother Kevin on Thursday night.
Kevin Mac Allister signed for Union Saint Gilloise earlier this year.
Ahead of their Europa League clash, Klopp said: "Yeah about his brother and their father is here, obviously family is here. A big moment for him, definitely, I am pretty sure. They have another brother I think who is playing as well professional football. Cousins playing professional football. The father was a professional player, uncle was a professional football player.
"I think it is not the first time that family members [are] on the football pitch, I would be really surprised, but yes, it is special. I saw a little thing when they spoke to each other. Brothers love each other but have still fights from time to time, or at least how I learned it when I was young. I didn't have a brother, but two sisters and that was bad enough!
"I think it is a special, nice side story but probably, hopefully, not the main story of the game afterwards."