The pair reportedly met in March when Lohan gave Farrell her phone number, Zap2it.com reported Friday. But upon learning she was only 17, he declined to respond.
Lohan turned 18 in July. At the time, she was dating Wilmer Valderrama. Then last week she and Farrell began spending time together during rehearsals for the episode of "Saturday Night Live" last Saturday that Farrell hosted, Zap2it.com reported Friday.
The pair reportedly went clubbing last Friday at the Marquee club, where they were seen kissing, and again Saturday night. About 7 a.m., local time the couple retired to Farrell's suite at the Plaza Hotel, Zap2it.com said.
Farrell plays the legendary ruler of Macedonia in "Alexander," which has only earned a little over a fifth of the estimated cost of production.