Lindsay met up with Sienna Miller’s ex at The Box on Chrystie Street in NYC very late on both Friday and Saturday nights, sources dish.

Her whirlwind weekend started Friday with dinner at Nobu Next Door before she headed off with her mom, Dina, and former Marc Jacobs boy toy Jason Preston to Stereo, where she greeted her friend DJ AM.

“She called Jude at 1 in the morning,” said our spy, “and met him at The Box.”

The next night, Lohan hit Cipriani Downtown for dinner, stopped by Beatrice Inn, and met up later with Jude at The Box again – this time joined by Law’s pals Sean Penn and Tim Robbins.

“They are adoring one another’s company,” said one sly observer, who could not confirm or deny any “dating.”