The TV and West End star claimed that it felt unusual to be spending so much intimate time with pro partner James Jordan, without there being a romantic angle.
Watch Denise's training video:
"The only time I've ever really danced with a man like this is when I'm going in for a cheeky snog," she said.
Speaking about her training sessions with Jordan, the theatre star compared the pro dancer to an "old lady".
"James is a right nag. I thought women could nag. My god, can that man nag," she said.
"He's like an old lady. An old lady after someone has stolen his biscuits. He gets aggravated, he gets irate. He's like a school teacher."
Meanwhile, Jordan claimed that judge Craig Revel Horwood would be very pleased by Van Outen's effect on him, joking that he would be like "a little sheep" by the end of the series.
Strictly kicks off on Friday night at 9pm on BBC One. The second show airs on Saturday at 6.30pm.