TV Series: Pretty little liars and an impersonator who calls herself Vivian Darkbloom. There's also a young girl called Mona, like Lolita's friend....(I didn't watch the program so I have no other information about the names in the series).

 

http://pretty-little-liars.wikia.com/wiki/Vivian_Darkbloom

After Caleb begins hacking "A's" phone, the girl's discover that Alison had created an alter ego, after she too was being victimized by "A."

Alison told Hanna she was tired of being herself so she created a new identity. She also spied on "A" as Vivian Darkbloom.

Vivian is first introduced when Caleb hacked the video to see her photo license. Hanna then remembers that she once saw Alison with dark hair in a
hair salon. She recognized her voice and was surprised to see her with a wig, but Alison told her that it´s just her hobby - pretending to be someone
else

§  The name "Vivian" comes from Latin, and it means "Alive."
§  The full name is also an anagram of "Vladimir Nabokov" who wrote the
novel "Lolita".
§  Very few people know Vivian's true identity, some of them are Duncan
Albert, the four liars, and possibly Mona Vanderwaal.
§  Since Mona is "A" it is unclear if she really saw Vivian or read about
her in Alison's diaries.