Lindsay Lohan SHOCKER On 'Anger Management' Set!!!

TMZ NEWS ALERT: Lindsay Lohan is NOT late for work.

We repeat ... not late. Our spies on the set of "Anger Management" tell TMZ ... Lindsay showed up at 9:15 AM PT for her guest appearance on Charlie Sheen's new show.

Here's what's shocking. She was not only not late ... she was EARLY. Lindsay's call time was actually 10 AM.

What makes this especially surprising is that LiLo is coming off a party weekend -- she was clubbing in San Diego Friday night and we got her at another club in Santa Monica Saturday night.