Why Frankie Muniz Hasn't Spoken to Hilary Duff in Over 20 Years

The actor detailed why his friendship with his Agent Cody Banks co-star ended after they wrapped the 2003 film, and put the blame on Duff's "super intense" mother, Susan, claiming she "pissed me off."

Frankie Muniz is revealing what allegedly led to the end of his friendship with Hilary Duff for the first time.

During an appearance on The Joe Vulpis Podcast last month, the actor detailed why he hasn't spoken to Duff since the two shared the screen in the 2003 film, Agent Cody Banks. And according to Muniz, 39, all of the blame is on Duff's mother, Susan.

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Muniz, 39, recalled how he became friends with Duff, 38, after he moved to Los Angeles to film Malcom in the Middle, noting that the two then-child stars "had a really great relationship for a long time."

However, he said it all went awry when he guest-starred on an episode of Duff's Lizzie McGuire in 2002.

"I don't know if I want to tell it, but maybe I will. It's been a long time," Muniz told podcast host Joe Vulpris, before then began.

"I was on the set of Lizzie McGuire, and I was in Hilary's dressing room, and her mom was there," he recalled, saying that Duff's mom, Susan, was "the epitome of a stage mom."

"She was intense. Hilary was so cool, we had an awesome relationship, but her mom was super intense," he continued. "My mom was the opposite. When I was on set, my mom would be there if she had to be, but she would hide in the corner. [She] didn't want to be in the way."

"I've actually never told this story, and I might get in trouble for it, but I don't care. I'm 40," Muniz joked.

According to Muniz, while he was in Duff's dressing room, her mom asked him about his summer plans, to which he replied, "Oh, I'm filming this movie where I'm playing like a junior James Bond. It's called Agent Cody Banks." Muniz said Susan then asked if there was a "girl" role that "would be good for Hilary."

"I was like, 'Yeah ... But I don't know,'" he told Vulpris, adding that he did have a "say" in his contract about his female counterpart in the film. According to Muniz, at the time, Smallville star Kristin Kreuk was being eyed for the part, admitting that he even "pictured" Kreuk in the role of Natalie Connors.

"So I really thought that was what it was going to be," said Muniz, who played the titular character.

However, he said the "next day" he learned "shocking" news from Duff's mom.

"The next day -- I'm not kidding -- the next morning ... I show up to the set, I go into [Duff's] dressing room to hang out. And her mom's like, 'Guess what? We're going to be spending the summer together!'"

"And I'm like, 'What do you mean?' ... She's like, 'We're going to be up in Vancouver together!' I'm like, 'Oh! What is Hilary filming? She's going to be filming a movie up there, too? That's awesome. We get to hang out, have dinners.' She [said], 'No, she's doing Cody Banks with you ... They signed the contract last night.'"

"The movie you knew nothing about yesterday?" Muniz recalled asking Duff's mom, adding that he felt that it wasn't "humanly possible." He said he called his agents -- noting that he wasn't "mad," it was just "shocking," especially because he had a "say" about the casting in his contract.

As for what apparently went down behind the scenes, Muniz said, "So supposedly calls were made, and they knew Hilary and I were really close, and I was filming her show, so they just assumed it was fine."

"Needless to say, I wasn't thrilled about it. And not because I didn't want it to be Hilary, just because [the studio went around him]," he explained.

Muniz said he was "fortunate" that he was able to have a "say" in casting, noting that he "had a certain image or a certain vision" of the character. He added that they had planned on auditioning other female actresses.

He went on to recall filming Agent Cody Banks in Vancouver, sharing that he "became best friends" with Angie Harmon, who starred as Agent Ronica Miles.

"We had such an amazing time on the set, [but] I was very sad when Hilary's mom would come on set. I'm being honest," Muniz explained, adding that he's now "old enough to where I realize I don't mind people knowing the truth."

He then dropped a sad claim: his friendship with Duff ended once filming wrapped.

"If I told you I've never talked to Hilary since the last day of filming," Muniz said. "I've not said one word to her since then. So that's the truth of that. No one knows about my Hilary Duff story."

When asked about the vibe between him and Duff on set, Muniz agreed that they were "professional," but said there was "awkwardness because maybe I left out there was a small dating element."

"So there was also that element that wasn't happening anymore," Muniz said. "It was awkward because of that."

Ultimately, he noted that he's sad he and Duff didn't remain friends.

"I regret not just continuing to be friends with her because we had a great friendship for such a long time, and I let her mom... it pissed me off," Muniz said.

He then stressed that he'd "love" to patch things up with Duff in the future.

"I would love to catch up with her," Muniz shared, before referring to the alleged drama with Duff's mom and the Agent Cody Banks casting. "I would love to even talk about that because I'm sure she doesn't know any of that happened."