After weeks of dating, a stunned Jennifer Aniston has discovered the new man in her life, Justin Theroux, has a startling gay secret.

The disclosure has rocked her relationship with the handsome ac­tor-screenwriter – who unlucky-in-love Jen con­sidered her “soul mate,” say sources.

After numerous failed romances and a dev­astating divorce, the “Friends” beauty believed she had finally found “the one”, but then a good friend of Jen’s was recently at a gay club “and overheard a bunch of men swooning over Justin,” claims an insider.

“The friend spoke withthe guys and learned that Justin is quickly becom­ing every gay man’s dream.

“I think Jen is in complete shock. It must be particularly upsetting because Justin never mentioned it to her, even though he’s blabbed to interviewers about his gay appeal and having a ‘man crush’ on actor Colin Farrell.”

The 42-year-old actress found her­self attracted to Justin, 39, when they worked together last fall on the soon-to-be-released “Wanderlust ” – and by May the two were spotted dating.

B u t pals believe Jen became furious with Justin for not being up-front about his icon status in the gay community.

I think she is having trustissues. Justin swears he is completely straight but has found in­credible success playing gay characters and is doggedly loyal to his fans.”

Interviewed by the gay mag “The Advo­cate,” Justin revealed he developed a man crush on Colin Farrell while the two thesped togeth­er on “Miami Vice.” He called Farrell “really charming and charismatic.”

In a candid admission, Theroux – who co-wrote “Iron Man 2” and “Tropic Thunder” –disclosed he wouldn’t rule out exploring his own gay side if the opportunity presented itself.

“I hope I’m comfortable enough in myself that if I even had a per­centage of any of that in me, I would feel free to explore it. Actually, I know I would.”

But pals say Justin will keep Jen in the dark about his appeal to gays “because he knows how very sensitive she is after being burned so many times.”