Attention MARTA riders: Get ready for a flesh mob.

If you see groups of hipsters riding MARTA trains without pants on Jan. 13, it's all part of the No Pants Subway Ride.

The event is part of a global No Pants Subway Ride started by Improv Everywhere in New York in 2002.

Atlanta's Gobi Lumberjacks have been participating since 2009.

This year's annual No Pants Subway Ride in Atlanta starts at the white arch near Underground Atlanta (across Peachtree Street from the Five Points MARTA Station). Those wishing to participate are asked to meet at 3 p.m. for instructions to be given out at 3:15 p.m.

The group is expected to ride the 3:45 p.m. northbound RED Line. They're expected to exit at the Civic Center, where they'll shed their pants.

After that, they plan to ride the trains to Lindbergh Station, then down to Airport Station before coming back to Five Points Station.

And in case you're wondering about indecent exposure laws, here is what the state statute says:

16-6-8. Public indecency.

(a) A person commits the offense of public indecency when he or she performs any of the following acts in a public place:

(1) An act of sexual intercourse;

(2) A lewd exposure of the sexual organs;

(3) A lewd appearance in a state of partial or complete nudity; or

(4) A lewd caress or indecent fondling of the body of another person.

A MARTA spokeswoman told East Atlanta Patch those riders — pants or no pants — will have to adhere to state and local public indecency laws.