Lindsay Lohan allegedly amused herself in rehab by wandering around naked to shock male patients and staff.
The Mean Girls star - who recently spent 45 days in Malibu's Promises Centre to be treated for alcoholism - was reportedly overheard bragging about her nude exploits at Allegra Versace's birthday party.
A source told National Enquirer magazine: "Lindsay was howling with laughter as she told all her friends, including Bruce Willis' daughter Rumer. They were all giggling too and their eyes were popping out.
"Lindsay said, 'I drove them all mad wandering around completely naked. They kept telling me to quit, but it was so much fun to tease all those boys. I just couldn't stop it!'."
Lindsay, 21, is currently trying to trace a hacker who stole naked pictures of her, taken by on/off lover Calum Best, from her computer.
The furious actress wrote on her internet message board: "All I know is that someone broke into my computer and left a file on my desktop saying they had the pictures Calum took of me naked. My lawyer knows about it.
"If I ever find out who broke into my computer, he is in big shit."
Lindsay has instructed her legal team to ensure the intimate images are never released on the internet as she fears they could ruin her career.