Adam Baldwin is set to return to ABC's Castle, signifying another Firefly reunion.

Why Is Rick Going Back To Work As A Private Investigator On 'Castle' Next Season?

Baldwin, who first guest starred in season 4 as Ethan Slaughter, is returning in season 8, according to a new Entertainment Weekly report. Fans will recall Castle (Nathan Fillion) following Ethan on a case in the episode titled Headhunters, though he eventually tired of Ethan's rough and tumble ways.

He will reportedly return in an early season 8 episode, though not much else is known beyond that.

How Beckett Will Be A Different Kind Of Captain On 'Castle'

This marks another reunion for Firefly, the short-lived sci-fi western series on Fox that was canceled after one season back in 2003. Fillion and Baldwin both starred on the show, with Fillion playing Malcolm Reynolds and Baldwin playing Jayne Cobb. The show has developed a cult following over the years.

Castle is undergoing a few shakeups with its dynamics, as Beckett (Stana Katic) becomes the new precinct captain. She is replacing Captain Gates (Penny Johnson Jerald), who will no longer appear on the series.

It remains to be seen if Castle and Beckett will still work and solve crimes out in the field, but this might be limited due to Beckett's captain duties.

The new season also introduces two new characters to the precinct - security specialist Hayley (Toks Olagundoye) and tech analyst Vikram Singh (Sunkrish Bala).

Castle season 8 premieres Monday, Sept. 21 at 10 p.m. ET/PT on ABC.

Tags: Castle television ABC