Let the great experiment begin!

We spotted Joaquin Phoenix, who may or may not be in the midst of a breakdown, shopping for lingerie with a mystery woman in Los Angeles yesterday afternoon. 

The grizzly-looking actor and his friend ducked into the upscale underwear joint Kiki De Montparnasse but kept their distance in front of our photog; who is this woman and what does she mean to the Quin?!

After they left the store Joaquin was dropped off at Raleigh Studios. Who knows if this beard/weirdness is for real or if Joaquin is doing some intense method acting, all I know is that there is definitely a hot dude under that mess and I want him to reemerge!