Kristin Cavallari says there won't be a 'The Hills' reunion because Spencer Pratt and Heidi Montag "pulled out".

Kristin Cavallari

Kristin Cavallari

The 31-year-old television personality would love a reunion show with her fellow cast mates but it won't be able to go ahead as the duo have "another contract" that blocks them from taking part.

Speaking on Sirius XM's The Jenny McCarthy Show, she said: "Truth be told, they were trying to get us all together. Then two people pulled out ... Well, it's for a specific reason they can't do it ... No, they have another contract so they're not able to do it. I'm spilling all the beans today."

And when Perez Hilton later question Spencer and Heidi if it was true, Heidi wrote on Twitter: "Like @KristinCav said it's a contract thing ... we want one [a reunion]! (sic)"

Whilst Kristin would love to return to 'The Hills', she previously insisted she won't let her kids - Camden, five, Jaxon, three and Saylor, two, who she shares with Jay Cutler - star on a reality television show.

Asked if she sees herself returning to similar series in the future by Heidi and Spencer on their podcast, she said: "I'm open to it, Obviously, the three of us come from similar backgrounds. The 'Hills' was a unique experience. I wouldn't trade it for the world ... To go back to that now as a mom and a wife, it would have to be different. I would have to be an executive producer. I would have to have more control and it would have to be more on my kind of terms. I would never put my kids on a reality show."