Vanessa Hudgens has opened up about what killed the relationship. Photo / Getty Images

Vanessa Hudgens has opened up about her relationship with Zac Efron.

The acting duo fell in love while filming the Disney blockbuster "High School Musical" in 2006 and were together for four years.

During that time, they shot three films as part of the franchise.

The announcement of their breakup in 2010 shocked fans around the world.

Hudgens, now 31, has opened up about what was one of the most high-profile Hollywood romances of recent years and how the pair dealt with fame.

"I remember one time we did have a fight, and it was while we were at rehearsals, and I remember Kenny Ortega [the director] coming around the corner with the most concerned look on his face like, 'Oh no, is our movie going to fall apart right now?'" Hudgens told the Hollywood Reporter's Awards Chatter podcast.

"I pride myself on being a professional, so I was like, that aside, we are going to move forward and do what we need to do, and we sorted it all out. I think because I was so young, having that relationship really stabilised me," she added

Hudgens revealed she first met Efron when they auditioned for the lead roles of Gabriella and Troy, and the attraction between the two was immediate. "Oh my God, this guy is so cute," she remembers thinking at the time.

"[The relationship] started off really organically, and I could not have been more grateful to have that relationship at the time," she said.

"[The movie] was this massive phenomenon all of a sudden and all eyes were on me … I had someone to lean on who was going through it as well."

Hudgens also said their relationship became strained at one point because of the attention Efron received from other women.

"I went through a phase when I was really mean because I was so fed up," she said.

"Girls were running after him, and I was giving them death stares. Then I realised that's not what that's about."

Hudgens has now been with actor Austin Butler for seven years.