'High School Musical 4' in the works

'High School Musical 2'

Disney has confirmed that a fourth High School Musical is in the pipeline.

The third instalment is currently filming in Utah and opens in US cinemas on October 24.

Executives said the new film is likely to be a TV movie like the first two, but that could change at a later date, claims The Hollywood Reporter.

They also said they were unsure whether the original cast - which includes Zac Efron and Vanessa Hudgens - will return, although new characters introduced in the third movie are expected to appear again.

Disney Channel Worldwide president Rich Ross said: "We are writing High School Musical 4. Are we going to have all the cast back? Probably not. Will we have some of them? I hope so."