For those not associated with either club, this came as quite a surprise. After all, they rarely play each other and are seperated by the River Thames but when the fixture list was released in the summer, this was the clash that both sets of fans were looking for first.
The rivalry stretches back over 100 years when Millwall used to play on the Isle of Dogs. Back then, the Hammers and the Lions were the two biggest teams in an area that was alive with football clubs and regularly competed against each other in the Final of the East End Cup. In those days it was all about trade pride - dockers vs iron workers - but that rivalry has remained down the years and reignited during the 1970s.
Since then, the two sides have only played each other on a handful of occasions but Sunday's game should see the old passion return, depsite the midday kick off.
West Ham go into the game as slight favourites, despite last week's defeat away to Gillingham. Trevor Brooking's only doubt is Michael Carrick and he should put out the same side that came from behind to beat Cardiff City in midweek.
Millwall, meanwhile, will be without Kevin Muscat who is suspended, although Abou Fofana could return to the starting line-up after recovering from a knock picked up during the victory against Wimbledon a fortnight ago.
Bob Peeters should partner Neil Harris up front if the latter recovers from a hamstring injury. Peeters has a good goal-scoring record in Millwall derbies in his brief time with The Lions and has scored against both Crystal Palace and Gillingham. If he scores on Sunday, his legend status will be pretty much guaranteed.
The game also sees David James up against his former understudy at Liverpool, Tony Warner. Warner has come on leaps and bounds since leaving his home town to join Millwall and his now rated as one of the best goalkeepers outside of the Premiership. Denzil, as he is affectionately known down The Den, will be keen to put one over his former colleague while David James will probably see this game as a dry run for when England face Turkey in October!
Either way, the passionate support of boths sides should make this eagerly awaited contest a joy to behold for the casual observer. One things for sure, it won't be a drab 0-0 draw.