1. Bob Denver

 

At the beginning of season three, a Russian spy who's a doppelganger for Gilligan descends on the island and holds him hostage. When the real Gilligan tells the other castaways, they accuse him of causing mischief. 

2. Leonard Nimoy

 

In the Star Trek episode "Mirror, Mirror," Captain Kirk and his crew land in an alternate universe where everyone has an evil twin. How do you know Spock's "twin" is evil? Just look at his menacing goatee. Of course, Kirk himself was split in two the prior season in "The Enemy Within."

3. Lisa Kudrow

 

Phoebe Buffay had a real evil twin in the form of the conniving Ursula, who constantly complicates her sister's life by sabotaging her romances and withholding important information. 

Image: Warner Bros. Television

4. George Reeves

 

The second season episode, "The Face and the Voice," of The Adventures of Superman was one of the first to feature an "evil twin" on TV. When a thug named Boulder undergoes plastic surgery to look like Superman, he uses his new appearance to bribe people out of money and donates it to charity. 

5. Liberace

 

It's hard to imagine a personality like Liberace relinquishing the spotlight to anyone, so it's fitting that when the time came to take a backseat, he did it to his own evil twin on an episode of Batman. The episodes which feature "Chandell" and his evil twin "Harry" were the highest-rated ones for the series. 

6. Tina Louise

 

When an unattractive woman named Eva appears on the island in season three, the women castaways end up giving her a makeover. The only problem is the makeover makes Eva look a lot like Ginger, and she uses her newfound attractiveness to take Ginger's place.

7. Jim Backus

 

The island was full of "evil twins," and even the millionaire wasn't immune. In season two, an imposter of Mr. Howell claims to have been rescued and starts spending all his money.

8. Elizabeth Montgomery

 

Samantha's evil twin Serena has a recurring role on Bewitched, which means viewers get to see Montgomery don some questionable black wigs throughout the series' run. It turns out Serena likes to steal the spotlight from her sister, too. 

Image: Sony Pictures Television

9. Barbara Eden

 

It must be a requirement for a woman with magical powers to also have an evil twin with a brunette wig. The only complicated part about Jeannie's evil twin on I Dream of Jeannie is that she's also named Jeannie. 

Image: Sony Pictures Television

10. Michael Landon

 

In season five's "Alias Joe Cartwright," when Little Joe is arrested after being attacked by a look-alike who escaped from an army prison, he has a hard time convincing the fort commander he isn't the wanted man. Doppelgängers were nothing new to the evil twin–loving Western. Back in season one, in "The Gunmen," both Little Joe and Hoss have evil twins, the Slade Brothers.

11. Chuck Connors

 

When a look-alike of Lucas McCain kills another man's steer, and then ends up killing the man himself, the real McCain find himself in trouble when the marshal wants to arrest him for murder. This season four outing was appropriately titled "Deadly Image."