Joan Rivers, Kelly Osbourne Mock Alicia Silverstone's Method Of Feeding Her Baby (VIDEO)

Earlier this week, we watched in horror and amazement when "Clueless" star Alicia Silverstone posted a video of herself feeding her 10-month-old son Bear Blu, by chewing up his food and spitting into his mouth -- just like mama and baby bird.

We weren't the only ones captivated by the bizarre mother-child interaction. "Fashion Police" co-hosts Joan Rivers and Kelly Osbourne found it downright hilarious. In a preview of the show, which airs Friday night, the duo take on the actress's strange parenting habits.

"We're a very happy group here, and we're like family, too," Rivers said, already trying to stifle her laughter as she took a bite of a giant sandwich. She then signaled to a bewildered-looking Osborne to move closer to her. "I dare you," Osbourne said to Rivers as she knelt by her side. Rivers then picked up a tiny piece of her sandwich, put it between her lips and and passed it along to Osbourne, mouth-to-mouth. Osbourne laughed and gave the thumbs up.

Silverstone also caught the attention of "Watch What Happens Live" host Andy Cohen, who dubbed the actress the "jackhole of the day" for posting the video. "I don't even care that she does it, it's her baby. I just had to give her the jackhole for posting it online and ruining my lunch. I was going to have a grilled cheese sandwich and I couldn't eat it," he said.

As unappetizing as "pre-chewing" might seem, Silverstone is not the only mother practicing this technique. According to a Center for Disease Control report, approximately 14 percent of caregivers in the U.S. engage in the behavior. While the practice has some documented health benefits, it also increases the risk of transmitting infection and disease between parent and child.