Aniston and a slew of other celebs have signed on for Stand Up to Cancer's first annual Twitterhunt.
Here's what’s going down...
SU2C has hidden T-shirts in more than 20 cities across the nation that have been autographed by folks like Aniston, Jack Black, Kirsten Dunst, Scarlett Johansson, Melissa Etheridge, Charles Barkley and Josh Groban, among others.
SU2C is twittering clues on their whereabouts, as are many of the celebs via their own Twitter accounts.
The hunt marks the one-year anniversary of SU2C. Tomorrow, the organization also announces the grant distribution of the more than $100 million it raised during its telethon last September.