Saif Ali Khan as Romeo,
A small cute looking pet of a super rich human family. He is a real good looking guy and he makes sure everyone around him thinks so too! He lives the good life. He has got a butler waiting on him, the best food to eat, a grand car to go out in and plenty of super rich friends. He is extremely popular with the ladies, he is a big flirt! He is very savvy and smart. When fate lands him in a slum, after his initial disappointment, he smooth talks his way out of trouble. He finds himself to be more intelligent than the average street guy and he takes full advantage of this fact to turn things around to his benefit. He thinks nothing of lying just to get what he wants.
Kareena Kapoor as Laila,
The lead singer and dancer at the Moonlight Nightclub. This is where all the males throng every week when she performs. There isn’t a male guy alive in the slum who doesn’t dream of dancing with the beautiful, Laila some day. In spite of the large list of admirers, Laila is a lonely girl. Charlie Anna, the Don of the slum, is besotted by her and everyone is terrified of his anger. The consequences of just talking to Laila can be fatal and due to this, she has no friends. The girls are jealous of her and the guys are scared of Charlie‛s wrath. She dreams of finding a sweet, honest and brave guy who will have the courage to be friends with her and dance with her.
Javed Jaffrey as Charlie Anna,
The dreaded Don of the slum. Anna means big brother and that is what everyone calls him out of fear. He is the cause of fear in everyone’s heart. He is dirty, fat and ugly, with a big bouncy belly. Charlie Anna is a pompous old fool who loves nothing more than hearing his praises. His moods are unpredictable and that is what makes him dangerous, yet at heart he is a hopeless romantic.
Vrajesh Hirjee as Guru,
The oldest and wisest among the four goons. The other three members always look up to him for advice.
Kiku Sharda as Hero English,
One of the four goons. He is a typical goon, a ruffian but a bit slow in the head, just like his three friends. Though he looks ferocious, he is a harmless chap. He has been born and brought up in this slum. Even though he has no clue, he is always trying to speak in English, to a very comical effect.
Suresh Menon as Interval,
The third member of the gang. He is a total film buff.
Tanaaz Currim Irani as Mini, the last member of the gang of four. Mini is actually an alley cat who is a wannabe stray dog. She looks up to Guru, Hero English and Interval and wants to be just like them. She is in denial that she is a cat. She refuses to accept that and thinks of herself as a stray dog much to the annoyance of her three friends who keep trying to drill some sense into her that she is no dog, but just an ordinary alley cat.
Sanjay Mishra as Chhainu,
Charlie Anna’s official spy. He is the yes man. A slimy character, he reports the goings on of the slum to Charlie. He is also responsible for reminding all to pay up their weekly protection money to Charlie on pay day.

Plot;

Romeo (voice of Saif Ali Khan) is a dog who once lived in luxurious surroundings. One day his owners decide to migrate to London and he is left at the mercy of the servant of the house, who dumps him on the street. Left to fend for himself, he is soon cornered by the local gang — Guru, Interval, Hero English and a dog-wannabe cat, Mini — who tell him that this is their domain. Romeo does not know the street lingo and is at a loss for words at first, but he manages to win the gang over with the idea of setting up a business.
Together, they set up a successful dog-grooming business until Chhainu (Sanjai Mishra), the right hand of gangster-dog Charlie Anna (Javed Jaffrey), arrives to collect “hafta” (weekly protection money) in the form of bones. Romeo throws Chhainu out, and the others, terrified, go to Charlie to plead their case. Charlie threatens them with his trio of ninja dogs, whom he calls his Angels (prompting him to crack a “Charlie’s Angels” joke), but Romeo tricks Charlie into allowing his friends to leave unhurt.
Romeo meets Laila (Kareena Kapoor), who is singing on a rooftop, and falls in love. To win her over, Laila tells Romeo he must dance with her in front of everyone at the “Moonlight Club” where she performs. Romeo says yes, unaware that Charlie Anna has long wanted her, and anyone who dares go near her is dealt with severely. However, Romeo braves the odds and dances with Laila to win her heart. Love blossoms, enraging Charlie, who captures and terrorizes Romeo. Thinking quickly, Romeo promises that he would make Laila fall in love with Charlie.
Romeo does not intend to lose Laila, but plans to deflate Charlie’s ego by having a disguised Mini pretend to be Laila and make it clear she’s not interested. This works, but only exacerbates Charlie’s ire, forcing Romeo to promise him a second meeting with Laila. The night of the appointment, however, Chhainu catches Romeo kissing Laila, who then learns of Romeo’s deal with Charlie and angrily says she never wants to see him again. A furious Charlie and his Angels chase Romeo and the gang, capturing them. However, the three Angels are wooed by Guru, Interval and Hero English and Charlie is chased and caught by the city dog catchers. In the end, Romeo’s selflessness saves Charlie Anna from the dog catcher; the two become friends, and Charlie himself brings Laila to Romeo in a train boxcar scene reminiscent of a similar, famous scene in the film Dilwale Dulhania Le Jayenge, causing Charlie Anna to remark, “Where have I seen this before?” In a dance number at the end, Romeo shows his left arm tattooed with Laila’s name.
“Bloopers” follow during the end credits.