Ashton Kutcher "So Pissed" Laura Prepon Kept Her Engagement to Ben Foster a Secret

"I had to find out in the news!" the actor complains to Kelly Ripa

Maybe Ashton Kutcher and Laura Prepon aren't as tight as he thought.

The actor guest co-hosted Live! with Kelly Ripa Friday when Prepon's recent engagement to Ben Foster came up. "I'm very upset with her right now. She just announced this engagement, and I had to find out in the news! She's my friend. It's weird like that," Kutcher said. "By the way, it's not just a random engagement. It's an engagement to another friend of mine! So, now I'm double upset that neither of them told me. I got off the plane in New York like, 'What?'"

To be fair, Kutcher kept his engagement to Mila Kunis a secret from Prepon back in the day. "When Mila and I got engaged, Pre was like, 'What? This is crazy! You guys, it was like 20 years ago. You were friends and no one saw this coming, and now you're engaged and I have to find out this way,'" Kutcher said. The four actors used to hang out regularly, too. "They were friends 20 years ago!" he recalled. "They're all my friends, and everybody's hooking up, and it's weird!"

Later, after the actors hugged, Kutcher told Prepon, "I am so pissed at you!" He then scolded his former co-star on Fox's That '70s Show, arguing it was "unacceptable" for her to keep Foster's proposal under wraps. "But if anyone understands [a need for privacy]," she said, "you get it."

"Oh, I get it. But 'private lives' includes friends!" Kutcher explained. "That's what happens! I shouldn't find out when I get off the plane!" Referencing her role on Netflix's hit series Orange Is the New Black, Prepon said, "I've been in prison! I have limited communication with people!" Kutcher then called out Prepon for "the amount of crap" she gave him and Kunis for getting together. "You and Ben Foster?!" he asked. "We've known each other all together just as long!"

There was no denying the facts. "It is true. We've known each other for, what, 20 years, right? Because we all started hanging out in 1998," the Girl on the Train actress said. "Every Friday after our taping, all of our friends would come hang out or whatever, and [Foster] was there."

Ripa then told Prepon she had read an article which claimed marriages last longer when the woman is given a round solitaire diamond—which is what Foster gave her. "I know how much you hate talking about this," Kutcher said as his friend blushed. "And it makes me so happy!"