On 'The Bonnie Hunt Show' (weekdays, syndicated), 'The Hills' star Kristen Cavallari offered her opinion on co-star Heidi Montag, who had a whopping 10 plastic surgery procedures in a single day, including breast and butt augmentation, brow lift, a second nose job and liposuction.

"I've known Heidi since she was 18 and I've seen this transformation ... it's sad," Cavallari said.

Watch the video after the jump.On 'The Bonnie Hunt Show' (weekdays, syndicated), 'The Hills' star Kristen Cavallari offered her opinion on co-star Heidi Montag, who had a whopping 10 plastic surgery procedures in a single day, including breast and butt augmentation, brow lift, a second nose job and liposuction.

"I've known Heidi since she was 18 and I've seen this transformation ... it's sad," Cavallari said.