It's one of the biggest games the Premier League has ever seen.
Monday's game between Man United and Man City is not only a local derby but it's probably going to decide who wins the title this season.
And behind this massive match, is years of rivalry. Man United have been on top forever but can city top off their dramatic rise to the top by beating their oldest foes?
Match of the Day Kickabout previews the derby of all derbies - and it's pretty dramatic!
It all started back in 2008, when City were taken over by super-rich owners.
Since then they have been getting better and better - but they still haven't won the league. Their dominant rivals, United, have always stood in their way.
But now, with only three games left, City have the chance to win the league. They are still three points behind United but if they win could catch them and go top on goal difference.
Does it get any bigger than that? Motd Kickabout think not!