Woof! Winona Ryder ain't the only celebrity in the dog house these days. Last week, Sharon and Kelly Osbourne never showed up at their own book party for Bark at the Moon: The Official Osbourne Pet Book (Pocket Books). An art gallery in West Hollywood was crammed full of stars and their pets — from Backstreet Boy A.J. McLean and his bulldog, Tank, to Survivor vixen Jerri Manthey and her dustmop, Gidget. But Ozzy's ladies were no shows. What gives?

Turns out, the overbooked Sharon was at the VH1's Big in 2002 Awards, where she accepted the "Strange But True" trophy for MTV's The Osbournes. Her guests were disappointed, but supportive due to the matriarch's medical condition. "I would love to meet the Osbournes," said American Pie starlet Shannon Elizabeth. "Sharon's a great lady. But she's only got a few good hours in the day right now, and she's got to take care of herself. That's what's important. She comes first."

Later, one gossipy guest — who dressed his teacup poodle in a blue Burberry cap! — told Party Boy: "You just missed David Faustino from Married … With Children. He left early because his big brown mutt was dragging him across the floor. It kept getting frisky with some of the other dogs!"