Ireland No 8 CJ Stander is expecting a backlash from "23 angry Englishmen" at Twickenham on Saturday.
England will be seeking to avoid a third consecutive defeat, and first at home under Eddie Jones, following a disappointing Six Nations campaign.
A victory for newly-crowned champions Ireland would secure just their third Grand Slam, but Stander believes this will be the toughest test of the championship for Joe Schmidt's men.
"There are going to be 23 angry Englishmen for sure," said Stander.
"When you play against England it is always another step up. I trained a lot with them during the Lions tour. Mako (Vunipola) has great hands while Maro (Itoje) is one of the most powerful I've played with and against. Dan Cole, another guy who works hard and loves his scrumming. As for Owen Farrell, he runs the whole thing.
"When they get on the field, they switch on. They're tough and they are physical. But they will be angry at what they have left out there so far in the Championship. And there will be some backlash from last year.
"This weekend is the toughest game (of the Championship.) There's a lot on the line for both teams."
Stander will be a key man for Ireland as he forms part of a formidable back-row trio alongside fellow British and Irish Lion Peter O'Mahony and rising star Dan Leavy.
England's struggles at the breakdown during this Six Nations have been well documented and Stander confirmed it is an area where Ireland will target.
"We've looked already at what they are doing and we know what we want to do against them," said Stander.
"Some small things have just crept in (to England's game), like at the breakdown, which has slowed down their game. Other teams have managed to compete well against them at the breakdown."
For Munster standout Stander, it represents the first title in his career but he knows this week is not the time to celebrate with a Grand Slam still to play for.
"I have never won anything in my career so I felt inside I wanted to flip the table and dance on it but I knew we had another game to go," said Stander.
"To win something, I didn't know whether to cry or to laugh. That five minutes celebrating with my wife was unreal. We were having beef wellington. England were still playing. Then they finished and we just looked at each other.
"I remember I was sitting next to Conor Murray, Earlsy, Garry (Ringrose) was there, and all of our partners. We were like, 'Congratulations'. Everyone was celebrating and enjoying it. Even the Scotland players had a few cheers. It was special.
"But we've got a week to go still. We need to make sure that we keep it inside. If you can get this right, then the celebrations on Sunday are going to be great."