Kylie Jenner wants control of her fortune and career now that she is 18.

Kylie Jenner

Kylie Jenner

The reality TV star - who is worth an estimated $5 million - reached the milestone age on Monday (10.08.15) and immediately told her mother and manager Kris Jenner that she wants to take charge of her own affairs.

A source told RadarOnline.com: "She hasn't even been 18 for a full day yet and is already acting like a terror by trying to call all the shots. Kylie is demanding that Kris give her access to her entire fortune immediately."

'Keeping Up with the Kardashians' star Kylie has reportedly turned to her older sisters for advice.

The insider added: "She has even been going behind Kris' back and asking her sisters how much money they get paid per episode for the show and how much money they each pay Kris for managerial fees.

"She is saying that it is her money and she wants all of it now."

Kylie recently splashed out on a $2.7 million mansion in Calabasas and her rumoured boyfriend, rapper Tyga, bought her a $320,000 Ferrari for her birthday.