Lindsay Lohan and Paris Hilton party hard

Lindsay Lohan has been partying with Paris Hilton.

The troubled actress celebrated the completion of filming of her small cameo role in musical TV show Glee by heading to the Bar Marmont, where she stayed until 1.30am this morning before moving on to a house party until 6am.

Click here to see Lindsay Lohan out of rehab

According to X17Online.com, Paris - who was previously good friends with Lindsay until a falling out - was also spotted at the house last night and the night before, sparking suggestions the pair may have become friends again.

Lindsay was reported to be a "total nightmare" on the set of Glee - which stars Lea Michele, Corey Monteith and Matthew Morrison - because she turned up late and did not know her lines.

A source said: "Lindsay was a total nightmare. She was three hours late in the morning and when she did finally arrive, she just didn't want to be there."

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However, her spokesperson Steve Honig claimed it was simply a misunderstanding.

He said: "The production team came to us and said that they wanted to start [with Lindsay] right after lunch, which was at 2. They wanted to begin with Lindsay at 3, so that meant she had a lot of time where she wasn't doing anything. That's why people didn't see her. She was then in hair and makeup and began after lunch at 3."