Where's Jen? Aniston MIA As Justin Theroux Grieves Philip Seymour Hoffman -- Living Separate Lives For Weeks

From Cate Blanchett to Amy Adams and Joaquin Phoenix, several A-list celebrities were on hand for the wake and funeral of Philip Seymour Hoffman in New York last week. But there was one person whose absence was glaring.

As a grim Justin Theroux said goodbye to his longtime friend and confidante, his fiancée Jennifer Aniston was nowhere to be seen. In fact, RadarOnline.com has exclusively learned, the couple hasn't been photographed together in public for more than a month!

The couple were last spotted together on a vacation to Cabo San Lucas, Mexico, in late December, but even then things seemed tense. Photographers captured shots of Aniston gesturing angrily at Theroux, and the two seemed distant.

They haven't been seen together since.

Theroux was last spotted in L.A. in mid-January, before fleeing back to Manhattan, even before Hoffman's death.

As RadarOnline.com has reported, he has never felt at home in L.A. and has publicly called the city "awful."

California girl Aniston, however, has stayed on the West Coast, where she was spotted attending Portia de Rossi's birthday party on January 31, just two days before Hoffman was found dead of an apparent overdose.

But more than a week later, she hasn't been spotted by her grieving fiancé's side.

The couple have been engaged for 18 months, but now it seems they've never been further away from walking down the aisle.