Kristi Noem's cross-dressing husband might have been exposed by an undocumented immigrant seeking retribution over President Trump's Department of Homeland Security policies.

Here's the deal ... Axios White House reporter Marc Caputo posted on X Tuesday that he received a "weird" tip in February about Bryon Noem's secret gender bending impulses, which include photographing himself wearing huge fake breasts and pink spandex shorts.

But, get this ... Caputo says the tipster was "an immigrant sex worker" who was possibly in the country illegally, and "wanted to go public about Noem’s husband using her services online -- it was vengeance for DHS’s immigration enforcement."

I truly don't care about his kinks. But props to the 'sex worker' for lighting this guy up.