Out of all the villains expected to bring chaos in "Gotham," none excites the fans more than Bruce Wayne's (David Mazouz) long-haired doppelganger. Could he be the long-lost brother, just like what the rumors are suggesting?

Last installment, Fish Mooney (Jada Pinkett Smith) escaped Hugo Strange's (BD Wong) laboratory. To get away from the guards and the Gotham police, she drove a bus containing some of Strange's experiments towards the city. A clear shot showed that one of the occupants bore an unerring likeness to Bruce. The copycat has longer hair, but the face is the same. There are a lot of speculations that the doppelganger is actually Bruce's brother, Thomas Jr.

According to The Hollywood Reporter, Thomas Jr. may have come to show Bruce exactly what he has become. In the many theories about his existence, one reports that Thomas Jr. had brain damage because of an accident that happened when he was still a kid. For everyone's safety, his parents placed him in a mental institution. Thomas Sr. and Martha died though and were not able to tell Bruce the truth about his brother. Thomas Jr. might have become one of Strange's experiments. In the comics, he turned out to be an assassin who went by the names Boomerang Killer and Owlman.

The third season of the FOX series will not air until September, but fans are already looking forward to the moment the look-alikes face each other. If Thomas Jr. is indeed Bruce's brother, the latter is in for a rough ride. There is no telling what Strange had done to him.

Meanwhile, showrunner Danny Cannon recently teased a photo of Mooney via his Twitter account. In the image, Smith's character is shown opening a double door. The EP aptly captioned it "Mooney's entrance."

"Gotham" season 3 premieres Monday, Sept. 19 at 8 p.m. EST on Fox.