Lindsay Lohan Nails 'Anger Management' And Charlie Sheen

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Lindsay Lohan proved why she became a star Monday as she aced 3 scenes for "Anger Management" -- this according to people on the set.

We're told Lindsay's first scene features her in bed with Charlie Sheen ... according to the script they had just had sex. We're told, "Lindsay knew her lines cold and her timing was perfect. She was really funny."

Lohan -- who showed up 45 minutes EARLY -- was "incredibly nice" and spent a fair amount of time taking pictures with the crew.

One source says Lindsay, who plays herself, "proved she has talent. You watch her and you know why she became a star."

Lindsay is back on the set tomorrow. One day at a time.

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