Heidi Montag Revisits Her Feud with Lauren Conrad on 'The Hills' : 'It Didn't Have to Go That Way'

Heidi Montag certainly has mixed feelings when she reflects on her relationship with Lauren Conrad, her former costar on The Hills.

Montag, 34, and Conrad, 35, were best friends during their time on the early 2000s MTV reality series until a feud over Montag's then-boyfriend Spencer Pratt tore them apart. Montag and Pratt, 37, have been married since 2008 and have a 3-year-old son together, Gunner.

During an appearance on the latest episode of Alex Cooper's Call Her Daddy podcast, Montag was asked for her thoughts on Conrad's success.

"I feel like Kristin [Cavallari], let's be honest, is the most successful," she said. "I feel like Lauren didn't make it like she should have. She should be Kylie [Jenner]. She was so good at makeup, she should have done the tutorials."

"She has a Kohl's line — great, whatever," she continued. "But she should be a hundred-millionaire, are you kidding me?"

Cavallari, 34, joined The Hills during season 5 after Conrad exited the series. She stayed with the hit show until it concluded with season 6 in 2010.

Though they gained considerable success on The Hills, Montag and Pratt have been open about their financial struggles over the years. In 2016, they told PEOPLE that just a few years into their Hills fame, they had squandered nearly their entire fortune.

"I was feeling so alone and defeated," Montag admitted of the time. "Everyone else on our cast had houses and we had nothing to show for what we'd done. I was like, the haters were right! It was sad."

Ultimately though, the couple said they learned valuable lessons through their past financial mistakes.

"Life is so short," Montag said. "And what matters is being happy with family and marriage and with personal progress. We're in a really good place."

Still, her and Pratt's continued financial issues were a plot point in the recently wrapped season of The Hills: New Beginnings on MTV.

Later on Call Her Daddy, Cooper, 26, asked about Conrad again. Montag said she's thankful that Conrad brought her onto The Hills and expressed regret over how their relationship fell apart.

"I'll always love Lauren, I appreciate everything she's done for me. I think that she never needed to do that," she said. "I always, she knows, was her best friend ... I was there for her for everything and it didn't have to go that way."

Montag went on to reference a sticking point in their friendship.

"She had a boyfriend I didn't like, when she was with Jason [Wahler], and I supported her," she said. "I literally was like, 'I'm your girl, I'm here for you, whoever you're with I just want to support you with.'"

She continued, "And then when that whole Spencer thing happened, she's like, 'Well if you date Spencer, you're off the show,' and I'm like, 'What? You are not the friend that I am to you, like why would you do that to me? I can't even believe you're doing this to me right now.'"

"How dare you, and I'm not your dog," Montag added. "Yeah, I appreciate you getting me on this show, but that doesn't mean you own me and you can tell me what to do in my life. I just don't appreciate that."

"I do have such a love for Lauren, and it didn't have to go that way," she concluded.

Back in 2007, Conrad told Seventeen that she'd been considering leaving The Hills ahead of season 3 because of her drama with Montag, though she ended up staying on through the middle of season 5 in 2009.

"I actually came dangerously close to not doing season three, because I really didn't want to do the show with Heidi and Spencer," she said. "I'm not who they are. I don't stage my own publicity. I just kind of live my life and do my job, and I don't want to be grouped with them."

Conrad has not commented on her relationship with Montag in recent years. The mom of two typically stays out of the public eye and chose not to return for the MTV reboot, The Hills: New Beginnings, to focus on her businesses and her family.

The entrepreneur and designer has built up her LC Lauren Conrad for Kohl's collection, has published nine books and is the co-founder, along with Hannah Skvarla, of The Little Market, a nonprofit marketplace.

"She loves being a mother and focusing on her family and on her work," a source told PEOPLE in 2018, when news broke of The Hills revival. "She has a very full and happy life."