Should A. R. Rahman win an Oscar on Sunday, the Indian film composer has written just the right tune for the occasion: "Jai Ho (Be Victorious)," the celebratory ode sung during Slumdog Millionaire's feel-good Bollywood-style song-and-dance finale.

The film's rags-to-riches fairy-tale plot might seem improbable, but Rahman identifies with the film's hero -- an orphan from Mumbai's slums who overcomes hardships to get a shot at winning a fortune on India's version of Who Wants to Be a Millionaire? as he searches for his lost love.

''I can relate to the film, because I take life positively and feel that even after great depression something good will come out,'' the soft-spoken 43-year-old composer says.

When Rahman performs his two Oscar-nominated songs, "O . . . Saya" and "Jai Ho" before a global audience at Sunday's Academy Awards ceremony, he will be realizing a dream. A deeply spiritual man, Rahman believes that music and film have the power to ''bring people together'' across boundaries of caste, religion, nationality and race.

Rahman, who has already won Golden Globe and British BAFTA awards for his score, says an Oscar would be a ''big dream'' to be shared with his millions of fans in India and elsewhere who have made him one of the world's bestselling recording artists, on a par with Madonna and the Rolling Stones.

With nominations for best song and original score, Rahman could equal in one night the total number of golden statuettes taken home by Indians in the Oscars' 80-year-history. Costume designer Bhanu Athaiya won for Gandhi in 1982, and arthouse director Satyajit Ray received a lifetime achievement award in 1992.

Rahman hopes an Oscar win will make Western audiences more aware of contemporary Indian film music.

''We have a different philosophy of approaching film music, and I would say there's lots to give, which I always wanted to happen,'' Rahman says. ``We've been great fans of films of the West, and we respect them so much and we also have certain qualities.''

Rahman had to overcome many hurdles on his path from his native Chennai (formerly Madras) in south India to the Kodak Theater for the Academy Awards ceremony.

After his musician father died when he was 9, his mother scraped out a living by renting out her husband's musical equipment. Rahman began supporting his family at 11 as a keyboard player in south Indian film composer Ilaiyaraaja's ensemble, and later formed a rock band and toured with such prominent Indian musicians as tabla maestro Zakir Hussain. He earned a scholarship to Trinity College of Music in London, where he studied Western classical music.

Back in India, he worked on advertising jingles until director Mani Ratnam tapped him to compose the score for the 1992 film Roja. Rahman ended up changing the face of Indian film music by introducing Western styles like reggae, rarely heard on Indian soundtracks.

''I think my philosophy of life is music is universal, . . . so I'm never closed to things,'' Rahman says. 'Like some people say, `Oh, I hate heavy metal,' or 'I hate jazz.' Why do you need to hate it? Why don't you appreciate it in a certain context?''

Western film composers began taking note of his work. Rahman's first major exposure to a larger Western audience came when Andrew Lloyd Webber asked him to write the songs for the 2002 London musical Bombay Dreams.

''Like any good artist, A.R. is not a traditionalist; he's a revolutionary. He uses all the revolutionary things that come from all over the world in his stuff . . . hip-hop beats, electronics, . . . and there's an incredible inquisitiveness and playfulness in his music,'' says the Oscar-winning, German-born film composer Hans Zimmer. ``Plus he writes a bloody good tune, . . . and at the end of the day it comes down to can the guy write a tune or not, and obviously he can.''

The composer's Slumdog success has led to offers from U.S. producers, but Rahman has no intention of abandoning Bollywood for the lures of Hollywood.

''Both of them complement each other beautifully, because I'm learning stuff from here and then giving it there and taking stuff from there and giving it here,'' Rahman says. ``India is going through this huge change in the whole vision of film making, and I want to be a part of that change.''