Lindsay Lohan Takes Li'l Sister to Tequila Party

Actress attends a bash and hangs by bar with her 17-year-old sister and Marilyn Manson the same day she swears to insiders that she's sober for life

How do you show you're serious about sobriety?

If you're Lindsay Lohan, you head to a booze bash at Chateau Marmont—and you bring your underage sister.

The very same day she swore to friends that she plans to stay sober for life (not just during her court-mandated probation), she hit the DeLeón Tequila two-year anniversary party with her 17-year-old sis Ali Lohan in tow:

She was spotted by the bar at Chateau Marmont, hanging with Marilyn Manson, but Lindsay tells us exclusively that she wasn't ordering cocktails. She was just simply attending the party to support the band.

"I don't drink," the troubled actress tells E! News today, adding "I was there to see The Kills because my friend's in the band."

Fellow guest Mischa Barton certainly seemed like she was having herself a good time.

"She came down from the party with a glass of wine in hand and tried to get into the locked pool area," an eyewitness tells me, "At the end of the evening, she had partygoers help her put her outfit together after she returned from the bathroom."

That's what friends (or assistants) are for, right?