Rachel Bilson is as big a Friends fan as anyone. But we’re not sure why she took this picture of herself on the Central Perk set, part of the Warner Bros. studio tour “Ross?” she captioned the photo.Friends has clearly stuck with Bilson, as it has stuck with all of us . We have some theories of what she’s doing with this photo.1. Maybe she’s shadow auditioning for a role in the upcoming musical 2. Friends' enduring popularity might also explain Bilson’s relative absence from the public eye. She’s probably been stuck binging old episodes on Netflix.3. Final theory: It’s not that she’s been raising a family, Rachel Bilson has clearly been developing the technology to digitally replace Jennifer Aniston. She’s been acting her way into the canon of TV sitcoms, but only she and husband Hayden Christensen know about it. This Instagram is her way of letting us know, “Hey, I’ve been secretly re-enacting Friends, digitally replacing Jennifer Aniston with myself, and this is my cry for help.”Then again, maybe she just took the studio tour like a normal human and found a good photo op.