A treasure lays buried deep at the bottom of an ocean. There are many people who want to get there by risking life, be it theirs or someone else's.'Blue' is touted as Bollywood's first underwater, action adventure thriller. Directed by Anthony D'Souza , the movie is inspired from Hollywood flicks like 'The Deep' or 'Jaws', but it is not a copy.The film is about a lost treasure, which three friends try to find undersea. Akshay Kumar , Sanjay Dutt and Zayed Khan play the respective roles.But in this hunt for the treasure, there's deceit and betrayal by someone in the group.Lara Dutta is paired with Sanjay Dutt in the film. The actress did not know deep sea diving before signing the film and underwent a rigorous Scuba diving training to prepare for her role.The movie's second heroine Katrina Kaif doesn't have a big role. But director D'Souza says Kat will surprise the audiences with her role. Sunil Shetty also has a brief role in the film.Most of 'Blue' has been shot in the Bahamas. Akshay, Sanjay and Zayed swam with real sharks while shooting their stunts in the film.While shooting one such stunt under water, Akshay Kumar had a narrow escape when he accidentally hit his head against the metal of a sunken ship and began bleeding. Blood attracted the sharks, but before any mishap could happen, the actor was safely pulled above water.To tone up his muscles, Sanjay Dutt hired the services of a special body building trainer from the US - Lawrence Gonsalves, who guided the actor on losing his former beefy body and developing a leaner physique. Special water-resistant make-up was required for the film's leading lady Lara Dutta. For that the producers roped in Hollywood make up artist Nikoletta Skarlatos.'Blue' also feature a special appearance by Australian pop sensation Kylie Minogue who has not only sung for the film but also shot a sizzling video with Akshay Kumar.Oscar winner A R Rahman has composed the tunes of the film's songs. In fact, Kylie Minogue agreed to sing and dance to her song in the film because she was captivated by Rahman's composition.The movie apparently also has an underwater song picturized on the entire cast.With a budget of over Rs 100 crores, 'Blue' is touted as Bollywood's most expensive film to date. Made under the banner of Shri Ashtavinayak Cinevision, the movie is set to release in May, 2009.