"What, she's engaged?" 30 Rock's Judah Friedlander said when PEOPLE broke the news to him on the red carpet at the Screen Actors Guild Awards Sunday in L.A. "This is the first I'm finding out. They've been going out for a long time, and he's a great guy."
But Friedlander's surprise over Bowden's impending nuptials comes from more than the initial not knowing.
"I like them both a lot, they're really good to each other, so I'm super happy – [But] I'm a little surprised to hear they're actually engaged," he said. "She's very young … Yeah, I am surprised."
Bowden, 23, who couldn't wait to flash her new bling for PEOPLE's cameras, gives her man, 28, props for selecting the perfect stone.
"I'm just excited to show it off and talk about it," she said. "He picked it all out himself from scratch. He knows way more about it now than I could ever know about picking out rings. I was truly surprised."
The actress put her love for Jorgensen on display at the PEOPLE/Entertainment Industry Foundation SAG Awards bash right after the show.
"The couple was hand-in-hand, kissing and holding each other," a partygoer says. "They were giddy-looking. At one point, Katrina shimmied to Michael Jackson's 'Don't Stop 'Til You Get Enough,' and she playfully smacked Ben's behind."
Inside the fete, Bowden said, "I feel like [a wedding] is such a big thing to plan. We have to figure out when we want to start planning it and go from there."
But don't expect her to turn into a bridezilla – at least not right away. "I can't imagine myself getting crazy," Bowden says. "But I guess you never know. I feel like until you become like a soon-to-be-bride, you never know if you're [going to be] crazy."
Additional peporting by Blaine Zuckerman and Melody Chiu