The couple were joined in the stands by their daughter Kelly and her fiancé Matthew Mosshart, as well as Jack's wife Lisa Stelly, who was cheering on for Jack as he danced the Cha Cha Cha.
It seems that Jack put on quite a showcase too. Teasing his performance, X Factor judge Sharon said: "@JackOsbourne is doing a big entrance tonight on @DancingABC that no one has ever done before. @KellyOsbourne & I can't wait!"
Jack dazzled the studio audience in a bright pink shirt to match the sparkly glitter dress of his professional dance partner Cheryl Burke.
Although 27-year-old Jack revealed that he was "super nervous" ahead of his performance, his sister Kelly couldn't have sung his praises higher.
Fashion Police co-star Kelly said she was "proud" of her little brother and told his dance partner Cheryl: "You are making my dreams come true I mean @JackOsbourne did the splits & wore a #HotPinkShirt tonight!"
Kelly later added: "@CherylBurke You are seriously turning @JackOsbourne into the twinkle toes I always wished he was! ;)."
One person who wasn't too impressed with the dance was Jack himself, who tweeted: "Well....that could have been better. The show must go on."
Sharon, who has just wrapped up filming the judges houses stage of The X Factor, later added: "@OfficialOzzy & I are so proud."