'This Is Us' : Sterling K. Brown Teases How Kate and Toby's Marital Issues Affect Pearson Family BBQ

"Kate gets divorced, it's not a surprise. A lot of people are thinking, 'She really gets divorced?' There's a wedding happening, and it ain't Kate and Toby," Sterling K. Brown tells PEOPLE

Photo: Joe Pugliese/NBC

This Is Us fans may not agree with the end of KaToby, but Sterling K. Brown assures audiences that there is a lesson to be learned from watching how the couple inevitably breaks up.

The last half of the sixth and final season is inching toward finally finding out how Kate (Chrissy Metz) and Toby's (Chris Sullivan) marriage leads to divorce. Last May, during a flashforward scene in the season 5 finale, viewers were shocked to learn that Kate remarries and finds love with her music school boss Phillip (Chris Geere).

Next Tuesday's episode, titled "Saturday in the Park," will be set at Rebecca (Mandy Moore) and Miguel's (Jon Huertas) anniversary barbeque in Los Angeles, where Kate and Toby's marital issues become even more evident to Brown's character Randall and the rest of the Pearson family.

"Boy, there's been a lot of stuff bubbling. We obviously know from the season 5 finale that there was a wedding that everybody was at — and it did not look like it was Kate and Toby's," Brown, 45, tells PEOPLE about what fans can expect in the upcoming 11th episode.

"I think [creator] Dan [Fogelman] and our writers have been interested in showing the different forms of family and giving value to all those different forms of family," the actor shares.

"Kate gets divorced. It's not a surprise. Like a lot of people are thinking, 'She really gets divorced?' Like, there's a wedding happening and it ain't Kate and Toby. There have been bread crumbs throughout the course of the season," Brown points out.

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All throughout This Is Us' final chapter, Kate and Toby have struggled to communicate effectively. They both finally feel happy and fulfilled in their respective careers, but Toby is working in San Francisco, which is over 380 miles from their two kids and their L.A. home base.

Though Kate recently visited her husband in the Bay Area, it was apparent that neither was willing to compromise, as Kate even called Phillip to be considered for a new role at the L.A. music school.

"It's sort of like a dissection of how two really good people, who are not antagonistic or mean or bad in and of themselves, can find themselves missing each other and how that reverberates through not just their own relationship, but through the rest of the family as well. That's what I can say about the party," Brown teases.

The three-time Emmy winner adds, "My wife and I have this conversation with each other all the time. If you're not growing together, you are growing apart. And there are times in which things can be like that. You have to make a real course correction to be like, 'All right, how do we get back on the same page?' Fifty percent of the time, people do. And 50 percent of the time they don't."

Joe Pugliese/NBC

Previously in season 6, a flashforward scene starring Kate and Toby's adult son Jack Jr. (Blake Stadnik) foreshadowed that Toby's favorite Big Green Egg smoker not only scars their son's face, but it also somehow contributes to the demise of KaToby. In last night's episode, Toby tells Kate that the smoker has arrived just in time for Rebecca and Miguel's anniversary celebration.

"Well, there's something aside from the Egg that occurs. Let's just say, it is not a normal party," Metz told PEOPLE about Rebecca and Miguel's upcoming anniversary barbeque.

"I don't know if the Pearsons can have a normal party, if I'm honest. S--- always seems to hit the fan with the parties. When three or more Pearsons are gathered, s--- hits the fan," she added. "I think it's because there's a lot going on under the surface — resentments and stuff that goes on. There's a particular incident that happens between Kate and Toby and Jack that really solidifies their decision of not moving forward."

And while fans are preparing to watch the unraveling of Kate and Toby's marriage, Brown shares how he's prepping for the end of the show. "We're getting to this place where last moments are starting to transpire in the history of This Is Us," he says.

RELATED VIDEO: This Is Us' Chrissy Metz Says It'll Be 'Really Difficult to Watch' Kate & Toby's Marriage Unravel

As for what he may want to take from the set as a keepsake, the star admits, "I haven't taken anything yet" but he might have his eye on certain items.

"There is a little figurine. As a matter of fact, I'm not going to take this. I think Sue [Susan Kelechi Watson] deserves this more than I. It's a little Black sort of Barbie doll thing that lives in our kitchen and it moves from different spaces all the time," he shares. "I just love the idea that they have this little Black girl figurine that has been a part of their lives for their daughters to see as they grow up, which would be cool to take."

Brown adds, "But there's also something about the Pilgrim Rick hat." (Randall's favorite holiday is Thanksgiving and the Pilgrim Rick hat is a special item that late Pearson patriarch Jack, portrayed by Milo Ventimiglia, had acquired from the front desk man at the hotel, where the family spent a memorable Thanksgiving after their original plans were ruined due to a flat tire.)

When asked about the possibility of his young sons, Andrew, 8, and Amaré, 6, mistaking the prized Pilgrim Rick prop as a Thanksgiving relic, Brown responds, "Oh, they'll totally rock it on Thanksgiving. Are you kidding me? I'll do it in a heartbeat. I will make it a Brown family tradition to wear this goofy hat. I would love it. It'd be awesome."

This Is Us airs Tuesdays at 9 p.m. ET on NBC.