Robert Forster Twin Peaks
Robert Forster has reportedly been tapped to replace Michael Ontkean in "Twin Peaks" after the actor decided not to reprise his role as Sheriff Truman. Above, Forster at Celebration Theatre's "30 Years Of Celebration!" benefit in 2013. Getty Images

"Twin Peaks" showrunners David Lynch and Mark Frost have been keeping details about the Showtime reboot tightly under wraps, but a new report suggests that fans won't be too happy with the latest casting news. While it has yet to be confirmed, Michael Ontkean reportedly won't reprise his role as Sheriff Harry S. Truman on the new series.

According to TV Line, the 69-year-old actor decided not to return for the reboot because he's "fully retired from show business,” a source said. The site reports that Robert Forster, 74, has been tapped to fill in. It's not clear if Forster will replace Ontkean as the new Sheriff Truman or if the series will create an entirely new character.

As previously reported, casting details about the limited-run series has been kept secret, but fans were happy to hear that composer Angelo Badalamenti is reportedly working on a brand new score for the reboot after providing the soundtrack for the original 1990-91 series.

If reports are true that Forster has been tapped to join "Twin Peaks," he will star alongside other rumored new cast members like Amanda Seyfried, Balthazar Getty, Peter Sarsgaard and Robert Knepper. The only confirmed casting news by Showtime is that Kyle MacLachlan is back as FBI Agent Dale Cooper.

It's believed fans can expect the series to premiere during the summer of 2017, even though Showtime President David Nevins seems a little more hopeful that "Twin Peaks" will be back on TV screens next year.

“I want it as badly and as soon as the biggest fans in the world want it,” Nevins said in August at the Television Critics Association Summer Press Tour. “I’m hoping we make 2016. It’s not clear. It’s ultimately going to be in [series co-creators David Lynch and Mark Frost’s] control. They’re going to shoot the whole thing and then they’ll start posting. Bottom line is I’ll take it when they’re ready with it, but I’m hoping sooner rather than later.”

Check out a teaser trailer for the "Twin Peaks" reboot below.