Hilton, who gained celebrity status when a sex tape she made with her boyfriend found its way on to the internet, insists the joke is on us.
She said: “I would do the baby voice and it’s kind of like this character I made up, but in real life I’m completely different, I’m very down to earth, I’m smart, I know what’s going on.”
The heiress made the claim in an interview with British presenter Fearne Cotton, who was visiting her Hollywood mansion for a documentary.
Explaining her alter-ego, she said: “It’s kind of like I almost play to the image and kind of have a laugh at myself about it.
“I think a lot of people will assume that I’m just like an airhead. But in my everyday life, when I’m hanging out with my friends or if I’m in a business meeting I’ll talk in my normal voice.”
However, her opulent Hollywood home seems at odds with Hilton’s claims she is “down to earth”.
She gives Cotton a tour around her vast colour-coded wardrobes, her secret passageways and her very own private nightclub.
The mansion even has its own miniature replica house complete with chandeliers, air-conditioning and furniture, for her dogs Prada, Dolce and Marilyn Monroe.