Stop everything you're doing: Jen has said goodbye to her long hair. We pretty much always keep a trained eye on Jennifer Aniston's enviable locks, so when we saw that she went for a chop, our hearts skipped a beat. Jen stepped out this week with a new short crop, bringing back the bob days of old!

This time, she apparently had a Brazilian chemical treatment that her hair didn't respond very well to, so she just lopped it all off.

We've seen her hair go through all sorts of lengths and styles, and it pretty much always looks incredible. We guess she's just a lady of perpetual good hair days! Must be her longtime hairstylist whom she loves so much, Chris McMillan (and the bevy of Living Proof products she uses) that keep it in tip-top shape. She dished about her new 'do last week, saying "It's short! It's at my jawline and a little shorter in the back."

Check out her hair transformation above, and see her new 'do over on PopSugar!