Before last week's action, both England and Ireland would've seen this rugby game as one of huge importance; now it's probably the biggest game either side will play this year.
France's surprise defeat in Rome means the winner of this game will be odds-on favourite for the Championship and the only side with a realistic shot at a Grand Slam, no disrespect to Italy.
Last season, England's scrum demolished Ireland on their way to a 30-9 victory; the previous year Ireland left England's Grand Slam hopes in tatters with a 24-8 win.
Off the pitch the two nations have a less-than-harmonious history, but on the pitch there is a grudging respect between the two.
If Ireland are to remain on course for victory, these are the keys to beating England.