Alec Baldwin may look to enlist the help of other celebs when his manslaughter trial over Halyna Hutchins‘ death gears up this summer — but there’s a catch … TMZ has learned.

Sources with knowledge of the case tell TMZ … the actor’s team is considering putting together a list of famous people to potentially testify on Alec’s behalf during his trial in July — but we’re told these stars would be people who’ve already spoken out in Alec’s defense.

Specifically, we’re told Alec and his team would possibly be eyeing public figures who’ve weighed into the issue of whether an actor can be held responsible for weapons on set.

Worth noting … our sources say this potential witness list hasn’t come to fruition just yet — remember, the trial is still months away — and we’re told nothing is set in stone either.

Still … if this comes to pass, it’d be major news — especially with the potential names.

So far … Alec has received public support from a number of stars, all of whom have taken a firm stance — namely, that it’s crazy to go after Alec for something he wasn’t tasked with checking in an acting capacity. Some of those names include Debra Messing, Mickey Rourke, DJ Qualls, Frances Fisher (who also starred in “Rust”) and others.

Interesting to note … some of these actors have already committed to being available in court if Alec should come to call on them — including Mickey … who tells us he’s game to testify.

Mickey tells TMZ … “Whatever Alec needs I’ll be there 100%. The armorer is 100% responsible for any gun handed to an actor. Especially, to an actor who didn’t have experience with guns.”

Rourke adds … nobody from Alec’s legal team has reached out to him yet.

As we reported … Alec pled not guilty to an involuntary manslaughter charge in January … over two years after he held the prop gun that went off and killed Halyna during a “Rust” rehearsal. Director Joel Souza was also injured at the time.

The armorer on set, Hannah Gutierrez-Reed, was just convicted of involuntary manslaughter herself — and while some feel that doesn’t bode well for AB … others disagree, arguing it only cements that the person responsible for weapons on set was found criminally liable.