Gwyneth Paltrow has accused Robert Downey Jr. of being a bad kisser.

The actress locks lips with the Oscar nominee in Iron Man 2, but the actor - who plays the title character and his alter ego Tony Stark - claims he deliberately toned down the passion to stop their smooch being “weird.”

“She said to me that I didn’t know what I was doing, like it didn’t feel good,” he said. “I’m like, ‘You know what? First of all, we’re all friends, so what would be creepy would be if I was coming off all sexy to you - which by the way, I’ve done in movies and it creeps them out. So what am I going to creep you out for?’”

However, despite Gwyneth’s criticism, the 45-year-old actor insists his co-star - who reprises her role as Pepper Potts in the sequel - really enjoyed their love scene.

“I couldn’t get her off of me. It was embarrassing,” Downey quipped. “Despite what she said on set, she still thinks about it.”

Speaking about their romantic moment, 37-year-old Gwyneth revealed there were other people on set to witness the event. “It was great because both my husband [Coldplay’s Chris Martin] and his wife [Iron Man 2 executive producer Susan Downey] were right there,” she said.