While it's not exactly breaking news to learn that The Hills was a heavily fabricated "reality" show, Heidi Montag exclusively told Life & Style that the MTV hit went to great lengths to try to keep that little known fact a secret while the show was airing.

In fact, the 29-year-old admits that while she didn't really have an actual job at Bolthouse Productions — the PR company she was seen working at on the show — she was expected to sit in the office during normal business hours and pretend to work … just in case someone called and asked for her!

"For the first season I really did work for Bolthouse for, I don't know, five months? But they just hired me for the show, so I literally had like, nothing to do," she said. "So I would just sit there and play Solitaire."

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The reality star also dished on her falling out with former Hills co-star, Lauren Conrad, adding that she was frustrated by how unsupportive she was of her relationship with now-husband, Spencer Pratt.

the hills

Heidi with the show's stars, Whitney Port, Audrina Patridge, Lauren Conrad and Jason Wahler.

"I think one of our biggest problems was that I was so supportive of her relationship with [ex-boyfriend Jason Wahler], and then the first chance she had to be supportive of me, she wasn't."

Luckily, the blonde bombshell has put her past behind her and is onto bigger and better things. You can catch her on Lifetime's new hit reality show, Mother/Daughter Experiment: Celebrity Edition, at 10 p.m. on March 1st!

Click through the gallery to see castmates of The Hills speak out about the show's authenticity!