Paul Lambert's side were humiliated by fourth-tier Bradford in the Capital One Cup semi-final on Tuesday evening, and the Barclays Premier League strugglers face potentially more embarrassment when they head to The Den to face the npower Championship Lions.
"We'll be the underdogs which suits us down to the ground, but the fans will get right behind us and they are very effective when they smell a bit of weakness," said Millwall goalkeeper David Forde.
"Villa will be wounded, though, and looking to right the wrongs of midweek.
"We know Villa are struggling at the moment. They are in a transitional period and going for a younger approach but they've still got loads of quality.
"This is a unique club with a unique stadium, The Den, and a cup game under the lights gives that added bit of spice.
"The fans will be preying on some of the younger players who have yet to experience that and hopefully it will work to our benefit.
"They make it an intimidating place to come. There will be 15,000 tomorrow but they will sound more like 30,000.
"It's a cup game, anything can happen. Hopefully if we can score first it will further dent their confidence and put some pressure on them.
"Since I've been at Millwall we've been concentrating on the league. But you see Bradford and Swansea getting to the final and say 'why not'? It can be done."
The match is being held on a Friday night because a demonstration is being held on Saturday against proposed cuts at the local Lewisham Hospital, an issue close to the hearts of many at the club.
Manager Kenny Jackett was a cup runner-up as a player with Watford, who lost 2-0 to Everton at Wembley in 1984.
Millwall were surprise finalists under Dennis Wise nine years ago but have not made much of an impact in the competition since - a fact Jackett is keen to address.
"We are really looking forward to facing a big club and established Premier League side," he said. "It's a fantastic opportunity for my players to show what they can do.
"Aston Villa have some fantastic attacking options and our defenders will have to do a good job. But if we can handle those perhaps we can exploit them going forward.
"In my time at Millwall a cup run is something we've lacked.
"It was a fantastic cup run with Watford, although the final was disappointing. But the cup run, the build-ups, waiting for the draw, is all a terrific memory.
"But these players aren't looking at the next tie or at a good cup run. They take each game on its merits and playing Villa at home, in front of 15,000 fans, their motivation will be different.
"You look at the Premier League and you can see the categories in the table. But the cup is unpredictable, it gives opportunities for upsets."