LOS ANGELES -- Ever since a Mayo Clinic newsletter mentioned this past October that Ken Burns' production company was spending time on the Rochester campus for an upcoming documentary, details have been sketchy.

So why not ask Burns himself?

Publicists had warned that their boss wouldn't spill many details about the project, so expectations were low when I sat down with the four-time Emmy winner last week to chat on more immediate matters, most notably "Vietnam," his much anticipated exploration of the divisive war. But he ended up freely expounding on his role on the Minnesota-based film, which is more prominent than initially expected.

"I'm way more involved than I'd thought I'd be," Burns said.

On a website for the Better Angels Society, the foundation that supports Burns' work and raises funds for them, it categorizes "The Mayo Clinic" under "Ken Burns Presents: The Next Generation," a division dedicated to a new generation of filmmakers with their boss lending his reputation and guidance as an executive producer.

But Burns says he's spending so much time on the project, he may end up with a co-directing credit.

The filmmaker behind "The Civil War," "Jazz" and "The Roosevelts" said the spark was set after a lunch with Mayo Clinic CEO John Noseworthy in 2010 when he was in the Twin Cities promoting a "10th inning" episode of "Baseball." Burns also noted that the Mayo is where he gets his annual checkup.

"I think it's certainly one of the most amazing medical places on earth and its story is unbelievable," said Burns who expects to deliver a fine cut by the end of the year with a PBS broadcast premiere in late 2018.

Burns' most high-profile priority over the next few months will be promoting "Vietnam," an 18-hour opus slated to air in fall 2017. That, too, has a Minnesota connection. One of the featured soldiers hails from Worthington, and Burns teased that the town opens up one episode "in a phenomenal way."

Burns said it's just coincidence that Worthington is so close to Luverne, Minn., one of the four cities that played major roles in 2007's "The War."