"We're still working on it. Still in negotiations," Brosnahan told ET on the red carpet ahead of Mrs. Maisel's PaleyFest panel at the Los Angeles' Dolby Theater on Friday. "Talk to Amy [Sherman-Palladino]. Ask her!"
"I feel like I'm not allowed to have any opinions about the show," she added, when asked who Brown could play. "Our writers are god here, and they would come up with something brilliant, I'm sure."
While Brosnahan's co-stars, Michael Zegen, Kevin Pollack, Caroline Aaron, Tony Shaloub and Marin Hinkle, told ET that they're hoping to to see guest stars like Steve Buschemi, Daniel Craig and Alan Arkin, creator Sherman-Palladino hinted that Brown is a safer bet to actually happen in season three.
Rachel Brosnahan Wants Sterling K. Brown on 'The Marvelous Mrs. Maisel' (Exclusive)
"[Brosnahan] doesn't have to campaign very hard. We all want Sterling K. Brown on the show," she shared. "Sterling K. Brown happens to be a very busy man. We love him. We are trying to find stuff that works with his schedule."
Executive producer Dan Palladino agreed. "It would be great. It would be fantastic!" he added.
"We're massive fans, and we just love him to death, so we would be thrilled," Sherman-Palladino insisted. "Thrilled, thrilled, thrilled."
Regardless of Brown's possible appearance on the show, it seems fans are in for a treat with Mrs. Maisel's upcoming third season.
"[The characters are] all alive," Sherman-Palladino joked when asked what's in store. "There will be skirts. There will be music and dancing and there will be a lot of fast talking, and we're going to see a little bit more of Susie and Midge furthering their partnership and what it means to be a road comic.
"We're sort of expanding on the idea that Midge's decision [to pursue comedy] became a hurricane and blew everyone off course, and everybody is finding their new reality this year," she teased. "It's big and scary, and [our crew] back in New York is crying."
The Marvelous Mrs. Maisel is available to stream now on Amazon Video.