The 35-year-old actress revealed that the Twilight heartthrob was suffering from a terrible cold, which zapped the sexiness out of the situation.
She told In Touch magazine, 'Rob possibly had the most hideous horrible cold of any co-star I've ever had to do a love scene with ever in my entire life.
'I'm going to say it's a little bit of a downer. I was a little disappointed. It wasn't sexy.
'He was literally snorting and snotting through every second of it - and it was not appealing. I'm talking green, infectious, disgusting - I'm not kidding.'