Who says it'll be a man that replaces Regis? Will Mark Zuckerberg make a cameo on SNL? And what's up with Kim Richards? Find out that and more with today's Showbiz Top 5!

5. Writers for "Saturday Night Live" are hoping to convince Mark Zuckerberg to make a cameo alongside Jesse Eisenberg, who played Mark in "The Social Network." Mark has complained that he wasn't portrayed fairly in the movie and sources say he's actually interested in doing the "SNL" bit.

4. Kim Richards reportedly has been hiding her alcoholism for almost 10 years now. "Star" magazine is reporting that this recent one-week stint in rehab wasn't her first. She actually went to rehab 8 years ago. It was right after her mother died from cancer and her divorce from billionaire Gregg Davis. She was a closet drinker and hardly anybody knew she had a problem until she checked herself in. Apparently, she didn't conquer the problem because we saw the poop hit the fan on the last episode of "Real Housewives of Beverly Hills."

3. Speaking of rehab, Demi Lovato reportedly will be checking out early next week. A source says Demi's been making some big changes in her life and she's excited about what the future holds. Demi checked in voluntarily to get help with her emotional issues after she sucker-punched a backup dancer she believed tattle-taled on her for partying the night before.

2. Everybody's been wondering what man is going to take over for Regis Philbin when he leaves "Live with Regis & Kelly." But why are we all assuming it's going to be a man? One of the names that keeps popping up among ABC executives is Lisa Rinna. She's co-hosted with Regis several times. She filled in for Joy Behar when she had to miss her show on HLN. She also took over for Billy Bush on the daytime version of "Access Hollywood" when he had to be out. And! When Kathie Lee Gifford left, Lisa was one of the finalists to replace her. But, of course, that job went to Kelly Ripa.

1. Charlie Sheen is in the hospital being treated for severe stomach pain. This comes after a marathon booze and cocaine bender with young porn stars. According to one of the blabbermouth porn stars, when she showed up at his house, Charlie was already drunk. She made herself a drink and she says Charlie grabbed the vodka from her and started chugging it straight from the bottle. A little while later, she says Charlie's dealer showed up with a designer briefcase full of cocaine, and Charlie pulled out a small green pipe and started smoking it non-stop for hours. When he started having horrible stomach pains, one of the porn stars called Charlie's neighbor for help -- Dr. Paul Nassif. He's the plastic surgeon married to Adrienne Maloof on the "Real Housewives of Beverly Hills!" He told the girl to call 911 and he did the same. Charlie was taken out of his house on a stretcher about 7am yesterday. Sources say he's being treated for a hiatal hernia, which he's actually had for years. Sources say Charlie's parents and his ex-wife Denise Richards were at the hospital with him.