The three stars of 'The Hangover' have signed up to make a sequel.

After weeks of rumours, Bradley Cooper, Ed Helms and Zach Galifianakis, will get around $5 million each for a second instalment of the comedy, while director and producer Todd Phillips is set to earn $10 million.

'The Hangover' - which tells the story of four men who go on a bachelor party in Las Vegas and three wake up the next morning with no memory of what happened the night before and have lost the groom-to-be - is the highest grossing R-rated comedy of all time, after becoming a surprise box office smash.

Cooper, Helms and Galifianakis made less than $1 million collectively for the original movie and were reportedly keen to get a much better deal the second time around, according to website deadline.com.

Justin Bartha, who played The Missing groom in the original, will also be back for the sequel, which is set to begin filming in October.

Although other cast members are yet to be revealed, Zac Efron recently revealed he would love to star in 'The Hangover 2'.

The 'High School Musical' heartthrob said: "I haven't got that call yet to join them but that would be amazing. I think that they're amazing and I love the cast that they've got going on."