Ashton Kutcher (who just revealed the gender of his second child) and Girl on the Train star Laura Prepon go back. Wayyyyy back. Back to 1998, when he first co-starred with the newly engaged brunette on the hit TV series, That ’70s Show.

HOLLYWOOD - MAY 06: Actors Wilmer Valderrama, Ashton Kutcher and Laura Prepon pose together at the Fox Television 'That 70s Show' wrap party held at Tropicana at The Roosevelt Hotel on may 6, 2006 in Hollywood, California. (Photo by Frazer Harrison/Getty Images)

Which is why he was so totally miffed to find out about her upcoming nuptials to Ben Foster (which she announced just days after former OITNB co-star Samira Wiley’s engagement) right along with the rest of us.

“I’m very upset with her right now,” he told Kelly Ripa on her talk show, LIVE With Kelly. “She just announced that engagement, and I had to find out on the news,” he lamented. “She’s my friend. It’s weird like that. 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?’”

Ashton got his chance to confront his friend just moments later, as she also “happened” to be a guest on the show. “He’s so pissed at me,” she says with a laugh before taking her seat.

“I am SO pissed at you,” he confirms. “Pre, Pre (his nickname for her last name) — this is unacceptable,” he starts in, shrugging off her “private lives” excuse. “Private lives include friends!”

NEW YORK, NY - OCTOBER 04: Laura Prepon (L) and Ben Foster attend the "The Girl On The Train" New York Premiere at Regal E-Walk Stadium 13 on October 4, 2016 in New York City. (Photo by Dimitrios Kambouris/Getty Images)

Not that he can *really* talk — apparently, he and Mila didn’t tell her when they became engaged, either — a fact she razzed them for, hard. “[After] the amount of crap you gave Mila and I!” he says.

“We’re really private!” she tells Kelly in defense.

We’ll say! We had no idea these two were even dating!

While it’s entirely unlikely Ashton will stay mad at “Pre,” it’s an amusing scene, regardless: Watch their “tiff” in the episode below!

Do you think Ashton has a right to be hurt? Share @BritandCo!

(h/t E!, photo via Frazer Harrison, Nicholas Hunt + Dimitrios Kambouris/Getty)