Heidi Montag Of 'The Hills' Reveals Why Mischa Barton Addition Was 'Frustrating'

"The Hills" certainly are alive from the sound of it. Reality star Heidi Montag shared in a recent Us Weekly interview that when former "The O.C." actress Mischa Barton joined the MTV cast for the series reboot, "The Hills: New Beginnings," she wasn't exactly thrilled with her new co-star.

"I think it was a little frustrating for me at first, because, like, we've put our whole lives into this show before and after, so to have someone come in and, like, be so reserved was a little bit confusing," the 32-year-old shared earlier this month.

Continuing, Montag said, "I don't think it was intentional, I think that is, like, how she is, and she's just a little more closed and needed a little more time to open [up]."

Montag was not the only cast member to harbor such feelings toward Barton. Co-star Jason Wahler also expressed similar sentiments when recounting how he initially felt about the new addition to the show, as reported by Popculture.com.

"She was very sheltered in the beginning. Very sheltered and shy and I think as I've gotten to know her... She was definitely..."

"...Misunderstood," Wahler's wife, Ashley Wahler, said.

Aside from the uncomfortable beginning, the cast seems to agree that Barton, 33, is a wonderful fit on the MTV reboot. "I think she's really quirky and funny and... She's a great addition to the cast. I really like Mischa," Montag concluded.

"The Hills: New Beginnings" premieres Monday, June 24, on MTV.