Palace have lost just one out of the seven games since Pardew took over, a run that has seen them climb to 13th in the Barclays Premier League and five points clear of the relegation places.
"It's Alan's confidence and enthusiasm - it's given the players belief, that's the best word for it," said Millen, who took over media duties as Pardew was suffering from a sore throat.
"He understands that before we were very structured and well-organised with a good defensive unit that counter-attacked well.
"That was our DNA before but he also wants us to develop our game and have more possession.
"The stats are showing that - we look dangerous, we look like we're going to get balls into the box and score goals.
"We're really pleased with how the players have bought into what Alan has asked.
"We're on a great run, the lads are confident, they're enjoying what Alan has asked them to do and that's showing on the pitch."
Pardew's side host in-form Liverpool in the FA Cup fifth round on Saturday, hoping for a repeat of their 3-1 win at Selhurst Park in November.
The Eagles also dealt a heavy blow to the Reds' title hopes in May last season, when they came from 3-0 behind to draw 3-3.
"We take confidence from our recent record, without a doubt," Millen said.
"The last two times they've come to Selhurst, they've had two tough games.
"I'm sure they feel they're in for a real tough one again tomorrow and we need to make sure we don't disappoint them."
Pardew is expected to overcome his illness in time for Saturday and the fixture will bring back fond memories for the Palace boss after he scored the Eagles' extra-time winner to beat Liverpool 4-3 in the 1990 FA Cup semi-final.
"The fans will remember that goal and getting to the final," Millen said.
"Those are the emotions you go through in the FA Cup and we want another day like that tomorrow.
"I was watching that game and I remember the occasion and getting to Wembley.
"We feel we're getting close to Wembley ourselves now so it's a big incentive."
Palace captain Mile Jedinak remains unavailable with an ankle injury but the club expect him to return to training next week.
Yaya Sanogo and James McArthur are also struggling with hamstring and thigh problems respectively, but January signing Pape Souare could make his debut after having a work permit application approved.
Source : PA