Lindsay Lohan was punched by a waitress at L.A. club Voyeur untimely Friday morning — her 24th birthday.

“A waitress just hit me – punched me for no cause,” the actress Twittered around 1 a.m. PT.

A witness tells UsMagazine.com that Lohan — who sipped Red Bulls and hid her SCRAM bracelet with thigh-high boots — wasn’t embellished.

“The waitress has a history with Doug Reinhardt, and Lohan was lynching out with him. She was envious, and out of nowhere, the waitress punched her in the face!” the insider tells us. “Doug didn’t desire any part of it and went to the other side of the booth. Lohan ran out.”

The night didn’t get enhanced from there.

Lohan went to a party at the close to Rockstar House — and ran into the waitress again!

“Lohan showed up and cried since the waitress was there as well,” says another source. “Some birthday.”