RJ Mitte Death: 'Breaking Bad' Costar Matt Jones Shares Heartbreaking Regret

RJ Mitte's "Breaking Bad" costar Matt Jones is heartbroken over his death ... and he's sharing a painful regret about the last time they saw each other.

Matt, who played Brandon "Badger" Mayhew on the hit AMC series, took to Instagram late Monday to remember RJ ... revealing they last crossed paths in January 2025, when they were cracking jokes in the back of a group photo and talking about their lives.

Matt says RJ had big plans for the future and wanted Matt to visit RJ's new place in Texas. The two even had plans to hit up a club owned by fellow "Breaking Bad" actor Steven Michael Quezada ... but Matt says he backed out because he was tired.

Now, he's wishing he'd gone.

"I'm so sorry," Matt wrote, adding he first met RJ 19 years ago, when RJ was just 15.

Matt ended the emotional tribute by saying, "I'm beyond devastated. You were a little brother to all of us. I'm so so sorry."

As TMZ first reported ... RJ died by suicide Monday at age 34.

Matt isn't the only "Breaking Bad" star mourning the loss. Bryan Cranston, who played RJ's onscreen father Walter White, shared a heartbreaking tribute Monday ... and Aaron Paul, who played Jesse Pinkman, has also honored his late costar.

RJ played Walter White Jr. throughout the show's five-season run.