The 32-year-old television personality weighed in during Wednesday's episode of Watch What Happens Live after Barton joined the MTV series The Hills: New Beginnings.
"It's interesting, I would say," she said with a laugh. "I was [surprised] too. I'm curious like everybody else to see it. I can't wait."
Cavallari teased drama to come for Barton, saying the 33-year-old actress had the hardest time with returning The Hills star Stephanie Pratt.
"I hear Stephanie Pratt is sort of stirring the pot," she shared.
Cavallari starred on The Hills during its original run on MTV but will not return for the reboot. She responded to her former co-star Whitney Port saying the group's trip to Paris on the show never actually happened.
"This is the first I'm hearing about this. That was pre my time. I've never heard that, but I can tell you most of my stuff wasn't real," the star said of her plot lines. "I'm going to take that road and say maybe it's true."
"I'm just happy that more people are finally coming out and saying stuff wasn't real, because for the longest time it was just me," she added. "So thank you, Whitney."
The Hills: New Beginnings premieres June 24 on MTV. Barton herself said in the April issue of Cosmopolitan there's drama to come in the new series.
"I sometimes get in over my head," the actress told the magazine. "I didn't really consider the fact that they're all such close friends. They're family girls. They all have husbands or ex-husbands and babies."
"I was afraid that, obviously, the drama would land on me because I don't have babies," she said. "But the bulk of the drama comes from the history they have."