I've watched her videos and seen her interviews. I like her videos, especially poker face. I like a lot of dance songs. Her songs aren't the best dance songs, but they're pretty good. I give her credit for making it this far. A lot of people don't.
1. She's extroverted as hell. It seems like she spends a LOT of time getting attention from people. She danced in burlesque shows in bars before she became successful. Why would an introvert choose that as a way to make a living? When she met with her fans, she signed autographs for ALL of them (a huge crowd) and she kissed and touched them too. Her materialism also points to her being an extrovert.
2. She has intellectual aspirations. She doesn't come off as shallow. So she's an N. She's into conceptual art and she wants to be like Andy Warhol. She's not like a sensor at all. Sensors are almost always strongly ANTI intellectual. They don't give a crap about intellectual concepts.
3. She's absolutely a Feeler. She cares a lot about people and relations. She goes out of her way to kiss up to people, make them feel good, get them to like her, and make connections. Also she donated money to Haiti.
4. She's ambitious and driven. She works hard. She's a J. Also, it seems like she is directing her own career in a calculated, planned fashion, using long term vision. This is a J thing too.
ENFJ
This description of ENFJ sounds exactly like her:
ENFJ Profile
And this sounds exactly like her too:
Portrait of an ENFJ
I saw how she acted with her fans. She was being totally ENFJ with them - giving them love & support and free pizza. She flatters people all the time. Tells them exactly what they want to hear.
She reminds you somewhat of ENTJ's and INTJ's because she's an NJ.
She's driven like an NTJ.