'Smallville' Star Allison Mack Gets GPS Ankle Monitor for Sex Cult Case

Allison Mack's every move is, officially, on Uncle Sam's radar ... the "Smallville" star is now rocking a sweet little GPS monitor on the heels of her sex cult arrest.

Mack, who was best known as Chloe Sullivan on "Smallville," is now known as the alleged pimp of a sex cult who got busted in Mexico last week. She was extradited to the U.S., and Wednesday in L.A. she got fitted with a GPS ankle monitor as a term of her bail.

Mack was indicted on sex trafficking and conspiracy to commit forced labor charges. She could get 15 years to life, if convicted. The FBI says she recruited and directed women, sometimes other actresses, to have sex with Keith Raniere -- the alleged leader of the cult -- who was also arrested.

Big bro's watching her now.