Nightie Night for La Lohan

Lindsay Lohan partied down in South Beach in what looks like a lingerie getup.

Sporting darker hair and a lacy black negligee, Lindsay partied at a Joe Francis event at Mokai in Miami Beach.

Lohan was seen with an unopened Rock Star energy drink in her hand as she exited the party -- looks like she's doing her best to stay sober. Goodnight.