Gwyneth Paltrow kicked co-star in the groin

Gwyneth Paltrow kicked Matthew Morrison in the groin when filming 'Glee'.

The actress makes a special appearance as substitute teacher Holly Holiday in the musical TV drama and Matthew – who plays Will Schuester – admitted she worried about hurting him as they danced together.

He told website Access Hollywood: "We're doing the Argentine tango, so you're in-between their legs and you're kicking up and stuff."

Pointing to his inner thigh, he added: "So she's kicking in here, and she's like, 'I'm so scared that I'm going to hit your man-love!'

"And I said, 'You know, just go for it.' And she did and she connected a couple of times."

Matthew added that the episode – due to air tonight (08.03.11) in the US - has a steamy theme and will feature Gwyneth's character teaching a class about the birds and the bees.

He added: "The episode is called 'Sexy' and Holly comes back as a sex-ed teacher and we teach the kids about sex through music."

While Gwyneth, 38, is married to Coldplay singer Chris Martin, Matthew is single and admitted he doesn't think he'd make a good boyfriend at present.

He explained: "I'm not dating anyone. I don't feel like I'm in a good place to be a good boyfriend.

"I know how much work it is to be in a relationship and I don't have the time to put in that work right now."