SHEFFIELD United currently sit top of the Sky Bet League One table, after recovering from a poor start to the season when they lost three of their first four games, including 2-1 to Millwall at The Den in August.
The Blades are 10 points clear of third-placed Fleetwood and can guarantee promotion by picking up 12 more points.
Striker Billy Sharp already has 26 goals this season and will be hoping to add to that tally on Tuesday night.
Millwall saw their 16-game unbeaten league run come to an end on Saturday after a 1-0 loss at Swindon. Neil Harris' men haven't won since beating MK Dons 2-1 on March 4.
Millwall are going for a fourth successive win over Sheffield United.
Lucas Ball spoke to Blades fan Chris Ward ahead of Tuesday's game.
Why do you support Sheffield United?: I was born and bred in the city, so supporting Sheffield United runs in the family. It was an easy decision.
Do you expect the Blades to go on to win the Sky Bet League One title?: Yes, I expect the Blades to go up as League One champions despite Bolton's late rally. It's been a long time coming after relegation in 2010-11.
After a 2-1 loss at The Den, how will United react against Neil Harris' side?: At The Den, you met a winless Sheffield United side. We breed confidence by topping the table now and are very strong at home, like yourselves.
Who are the Blades' most dangerous players?: Billy Sharp, the country's leading scorer who's supplied by a very talented midfield in John Fleck, Mark Duffy and Paul Coutts. Kieron Freeman also has eight goals from wing-back, so we have a lot of attacking threat.
Who do you expect to be a danger from Millwall?: Obviously the front pairing of Steve Morison and Blades fan Lee Gregory is a potent force with a serious threat to United gaining a positive result.
They haven't been as solid this year as last, but on their day are a handful for any defence.
What's the likely line-up and formation?: 3-5-2/3-4-1-2: Moore; Basham, Wright, O'Connell; Freeman, Coutts, Fleck, Lafferty; Duffy; Sharp, Hanson.
Finally, a score prediction?: Sheffield United 2-1 Millwall, possibly with United having to achieve this after going behind.