Actress Ashley Tisdale has blasted rumours her High School Musical co-stars are jealous of the romance between Zac Efron and Vanessa Hudgens.

Efron and Hudgens began dating after they appeared together in the first installment of the film franchise.

But Tisdale, who plays Sharpay Evans in the hit movies, insists their relationship did not cause any problems on-set.

She says, "Vanessa and Zac are a great couple. We're all like brothers and sisters on the set so there's no jealousy about their romance.

"It's very sweet to see them so romantic and none of us mind seeing them like this together. They are as much in love off-screen as they are in Hsm. There's such a great chemistry that it is like a fairytale."