Viewers of The Hills and of The Hills: New Beginnings know that Spencer Pratt can be a royal jerk.

His castmates know it -- including former castmate Lauren Conrad.

Heidi Montag says that Lauren once threatened to have her booted from the series if she didn't dump Spencer.

She also says that Lauren treated her like a "dog" ... and could have been a makeup mogul like Kylie Jenner.

This week, Heidi Montag was a guest on Alexandra Cooper's Call Her Daddy podcast.

Alexandra had praised Lauren for opting out of the ongoing "scramble" for fame.

Heidi shared that she has a slightly different take on her former castmate.

"I feel like Kristin, let's be honest, is the most successful," Heidi said.

"I feel like Lauren didn't make it like she should have," she opined.

Heidi added: "She should be Kylie [Jenner]."

"She was so good at makeup," Heidi explained, seemingly praising her friend.

Still speaking of Lauren, she added that "she should have done the tutorials."

"If she had a good team, she'd be a billionaire," Heidi estimated before revising: "She'd be a hundred-millionaire."

"She is not where she should have been at all," Heidi opined.

"She has a Kohl's line," she acknowledged dismissively. "Great, whatever."

"But she should be a hundred-millionaire," Heidi insisted, "are you kidding me?"

"Who gets that big promotion, that big fame," Heidi began.

"That big engine behind her, the loved one, the this-and-that," she continued.

"The narrator," Heidi continued. "No one even gets the narrator show."

"Kylie didn't get a narrator show," Heidi pointed out.

Describing Lauren, Heidi added: "She should be so rich."

It's sort of a backhanded compliment to say that someone could be mega-wealthy but totally threw away their chance at it.

Still, Heidi insisted that she will "always love" Lauren.

She still credits her for giving her a start in the entertainment industry.

But Heidi recalls how her husband, Spencer Pratt, was viewed and treated by Lauren early in their relationship.

"When that whole Spencer thing happened," Heidi recalled.

She accused Lauren of demanding that she drop her now-husband.

According to Heidi: "she's like, 'If you date Spencer, you're off the show.'"

"How dare you," Heidi responded, her indignation just as palpable all of these years later.

"And," she continued, "I'm not your dog."

Apparently, her gratitude for what Lauren did for her only went so far.

"Yeah, I appreciate you getting me on this show," Heidi characterized her reaction.

"But that doesn't mean you own me," she noted, "and you can tell me what to do in my life."

Heidi expressed: "I just don't appreciate that."

"I do have such a love for Lauren," Heidi then claimed.

"And," she added, "it didn't have to go that way."

"She chose and wanted it to go that way," Heidi accused.

"And then kept following up with that," Heidi said.

"And," she went on, "then kept blaming things on me."

Heidi added that Lauren was resentful of her "and blaming her sex tape on me."