The 50-year-old actor couldn't contain his excitement when talking to ET's Carly Steel about being a dad for a third time.
"I'm always excited about kids. I prefer being around kids. You know, they have the imagination. They're fun," Brolin said while at the premiere of his latest film, Sicario: Day of the Soldado, on Tuesday. "I've heard other people be like, 'Kid's sitting there, he's staring at nothing, he's slobbering, like, what's the point?' The point is to sit there and slobber with him. That's the point."
Brolin -- who announced that wife Kathryn Boyd, 30, was expecting back in May -- also noted that he and the mom-to-be are "appropriately nervous" about becoming parents together but are also "really looking forward to it." This is Boyd's first child, while Brolin has two grown children, Eden, 24, and Trevor, 30, with first wife Alice Adair.
The Deadpool 2 star revealed who else is looking forward to the baby — his step-mom, Barbra Streisand.
"The kid has a great Jewish grandmother and she's appropriately manifesting like she should," Brolin said of Streisand who's married to his dad, James Brolin. "She's into it, she calls every day, she follows the app. It's amazing. It's amazing. Look, it could've been the opposite and it's not so we love that people are involved, family's involved, friends are involved. It's a good thing."
As for his relationship with Boyd, whom he wed back in 2016, Brolin can only hope to emulate what his dad and Streisand have had for 20 years.
"You know, my dad, like myself, has been married before and for some reason this just clicked and it just made sense from the beginning," Brolin -- who was married to Adair and Diane Lane -- said of his father's previous marriages to Jan Smithers and Jane Cameron Agee. "You never know, you have your fluctuations in a relationship and after 20 years, they're looking at us going, 'Can you believe it's 20 years? I can't believe it's 20 years. So, we hope the same for us."
Now that his busy months are wrapping up — Brolin recently starred in Deadpool 2 and Avengers: Infinity War — the A-list actor is looking forward to a possible babymoon with his wife, but not before urging people to see his latest movie, Sicario: Day of the Soldado.
"It's one of those things that if you saw the first film, you're going to like the second film period. But it's a very different film. It stands on its own. It's a very adventurous film. It's a very personal film. It's very intense," Brolin said of the sequel. "I mean, if you like this kind of film, this is the film to see. There's a lot of tent-pole movies coming out and you need this kind of film. I think that's why they released it in the summer. It's a perfect time for this film."
Here's more on the movie, which hits theaters on June 29: