Former Olympic champion Audley Harrison claims he had an encounter with Lindsay Lohan over the weekend at Chateau Marmont ... while he was "in the toilet."

Harrison tweeted the above on his Twitter account. A source inside Chateau tells X17online exclusively:
    "Lindsay was acting so crazy. She was drinking vodka and Red Bull and kept going in and out of the men's bathroom every ten minutes. We were all totally creeped out. She ... kept banging on the men's cubicle door calling for some guy named Andrew. It happened to be the pro boxer Audley Harrison. He came out of the bathroom and was telling everyone about it and laughing at her."

This past Friday, Judge Stephanie Sautner sentenced the starlet to 120 days in jail for violating her probation. However, she only served 5 hours after posting $75,000 bail.

Find out when Lindsay is due back in court ... after the jump.