Anfield chief Rafa Benitez and Allardyce make no secret of their dislike for each other.
And though Blackburn boss Big Sam plans to watch from the Ewood Park stands, he will have no worries about coming down to get under the skin of Benitez if necessary.
Rovers No2 Neil McDonald said: "Sam will be upstairs on his phone shouting and bawling in my ear as usual. If it goes really well then, hopefully, he sits upstairs.
"If he needs to come down, then he can.
"Liverpool are a star attraction, always have been and always will be, so it's a fantastic game for him to come back into. He loves pitting his wits against the big four."