Wyatt Russell, who is 8 years younger than his sister Kate Hudson, tells PEOPLE that he got a little emotional when he heard her big news

Wyatt Russell is over the moon for his pregnant sister Kate Hudson, who’s expecting a girl.

The 31-year-old actor tells PEOPLE that he got a little emotional when he heard her big news. The actress, who turns 39 Thursday, is expecting her first daughter with boyfriend Danny Fujikawa after having two boys — Ryder, 14, and Bingham, 6 — in previous relationships.

“I was happy. I was teary-eyed because I know how badly she wanted a girl,” he says. “I know Danny, I’m sure in some part of every man’s brain you’re like, ‘I’d love to have a little me.’ But when he met my brother’s little girl Rio [Hudson], who’s the cutest thing in the entire world, she made him be like, ‘Okay, I want a girl.’ So they’re really excited.”

Hudson revealed her exciting news on April 6 via an adorable Instagram video showing the actress scream for joy after popping huge balloons that revealed the sex of her third baby. Russell couldn’t be there because he was working, “which sucked,” but he says his whole family — including actor parents Kurt Russell and Goldie Hawn — are “super happy.”

The little one on the way joins brothers Ryder and Bingham as well as actor Oliver Hudson’s children — Wilder, 10, Bohdi, 8, and 3-year-old Rio. Hudson is following in her older brother’s footsteps in having two boys before finally welcoming a girl.

The whole clan in 2016: Oliver Hudson, Kurt Russell, Goldie Hawn, Wyatt Russell and Kate Hudson with kids Wilder Hudson, Rio Hudson, Bingham Bellamy, Ryder Robinson and Bodhi Hudson
| Credit: Todd Williamson/Getty

Fujikawa’s side of the family is just as excited.

Earlier this month at Daily Front Row’s fourth annual Fashion Los Angeles Awards, Hudson’s best friend (and Fujikawa’s stepsister) Erin Foster opened up about the happy couple and their daughter on the way, explaining it will be “interesting” to see their parenting dynamic.

“Kate is a really good mom. She’s strict. She’s really good with boundaries. She’s tough,” Foster told PEOPLE. “And Danny is like a hippie. He’s very ethereal and go-with-the-flow, so it will be interesting to see how that happens.”

Since announcing her bundle of joy on the way, the How to Lose a Guy in 10 Days actress has appeared in Hong Kong to help cut the blue ribbon at the House of Harry Winston‘s second retail store opening, as well as alongside Fujikawa at Gwyneth Paltrow‘s star-studded engagement party over the weekend.

Although the actress’ baby news came as a surprise to her fans, a source previously told PEOPLE that the couple are “very happy” because they had “been trying to get pregnant.”

Russell next stars in AMC’s show Lodge 49, coming this fall.