I'm writing this about two hours before the 2007 Oscar nominations are revealed, three days after seeing Dreamgirls, and just under 20 hours after I met and interviewed Jennifer Hudson, who seems a cert for a Best Supporting Actress nomination and a likely winner (if this endorsement doesn't jinx her chances). She really should get it. A big girl with a huge six-octave voice, Hudson came seventh in American Idol in 2002 (Elton John claimed it showed the show was racist) and had never acted before winning the role of Effie White over 781 hopefuls, although you wouldn't know if from her sassy, assured performance.

In Bill Condon's adaptation of the hit Broadway musical inspired by the story of the Supremes, the glam role of Deena Jones/Diana Ross goes to Beyonce Knowles, who looks great in a sequined sheath but who acts like a nodding dog. Effie, based on the ousted founder of the Supremes, Florence Ballard, is the big dramatic part and she gets the show-stopping, lump-in-the-throat, something-in-my-eye number, And I Am Telling You I'm Not Going. In 1981 another Jennifer, Jennifer Holliday, was catapulted to immense fame in the US when she sang the song in the original Broadway Dreamgirls: I saw her do it, aged 15 (me, not her) and it is one of the most potent theatrical memories I have. It's not faint praise to say that Hudson's rendition equals it.

So, she should win (Dreamgirls should not win best film: although nowhere near as inert as the awful film musicals of Chicago and The Producers, it still gives off a slight greasepainty staginess). But Hudson should also beware. Those that the Gods wish to destroy they first give a "most promising" award, and those awarded for a supporting role can often find themselves stuck there: like Eve Marie Saint (On the Waterfront, 1954) Rita Moreno (West Side Story, 1961) and Mira Sorvino (Mighty Aphrodite 1995), to name but three.

Then again, Hudson may not care. "I always thought I'd win a Grammy for singing first," she told me unselfconsciously yesterday, still reeling from her Golden Globe award and the mere whiff of an Oscar, adding that the music business was far more obsessed with image than the movies. Such candour is a delight and a rarity in either world. If she does win, her plain-spoken acceptance speech should be a joy to hear.