Billy Baldwin is voicing his support for brother Alec Baldwin's upcoming "Rust" premiere ... saying the event isn't as controversial as one might think.

We caught up with the actor outside the "Americans With No Address" premiere in Los Angeles Thursday evening, where BB took a couple minutes to defend "Rust" moving forward with a red carpet debut -- despite the on-set tragedy and subsequent manslaughter trials.

As Billy put it ... Alec and the rest of the "Rust" creative team are honoring the wishes of the family of late cinematographer Halyna Hutchins ... who was fatally shot on the set of the Western flick in 2021.

He noted ... "My understanding is that's the wishes of her family and her husband. I think they wanted to honor her by having her work finished and by having her work seen."

However, don't expect Billy to be in attendance at the premiere ... as he'll be attending a different festival in Siena, Italy for a movie he made with Michael Madsen and Judd Nelson.

News of the "Rust" red carpet premiere broke Thursday, when it was confirmed the film will debut at Poland’s Camerimage International Film Festival in November.

Festival director Marek Zydowicz defended the decision to premiere the controversial movie, noting the film festival was one "important" to Haylna ... who was born in Ukraine when it was part of the former Soviet Union.

Zydowicz added ... "During the [2021] festival, we honored Halyna’s memory with a moment of silence and a panel of cinematographers discussed safety on set. Now, once again, together with cinematographers and film enthusiasts, we will have this special opportunity to remember her."

Alec, who held the gun that fired and killed Haylna, is not currently slated to attend the festival.