Los Angeles, California - Megan Fox has stirred up controversy online over her Halloween couple's costume with fiancé Machine Gun Kelly. Here's why.

Fox (36) posted photos of the duo's Kill Bill-inspired Halloween weekend costumes on Instagram on Sunday, making sure to tag the still-striking SAG-AFTRA union in the post's caption.

The tag appears to be in reference to the union's request for stars to abstain from industry-related Halloween costumes while the SAG-AFTRA strike is still on.

Veteran actor Lisa Ann Walter (60) criticized Fox's actions in her own social media post.

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"What a rebel. Keep posturing for stupid s***, pretty lady," Walter wrote on X. "Meanwhile we’ll be working 10 hours a day – unpaid – to get basic contract earners a fair deal."

"PS – the post responded [to] members questions. No one cares about kids’ costumes," Walter added, noting that the union was only worried about "high pros at fancy parties. Like Megan."

The backlash against Megan's post was immediate, as more commenters flooded her comments section with their displeasure.

"girl, you did not just tag sagftra," one comment reads, with another saying, "Isn’t this group you’re rebelling against trying to HELP you…?"

Some users got pretty savage, with one writing, "Lmfao. You tagging them like if you’re actually booking anything." Another commenter noted Fox and Kelly's rocky relationship status, asking, "Y’all are still together???"

Talks are still ongoing between SAG-AFTRA and major fulm studios like Netflix and Disney, while the WGA ended their strike in early October.