Hudson found Oscars success after being rejected from American Idol

The city's mayor Richard Daley declared Tuesday "Jennifer Hudson Day", describing the Dreamgirls actress as "an inspiration to everyone".

Large crowds cheered the singer and actress, who went from an American Idol reject to winner of best supporting actress at this year's Academy Awards.

She told fans: "Not only can I do it, but you can do it, too."

Earlier, Hudson was greeted by thunderous applause when she spoke to students at her former high school, Dunbar Vocational Career Academy.

In Dreamgirls, Hudson portrayed a vocalist cast out from a 1960s girl group.

The role came barely two years after American Idol judge Simon Cowell told Hudson she was "out of her league" and she was voted off the TV show.