Julie Chrisley & Jerry Harris

"Cheer" star Jerry Harris and Julie Chrisley are 2 names you'd never expect to see in the same sentence, but they're now sharing the same address ... in a federal lockup.

Here's the deal ... Harris, an ex-cheerleader from the Netflix hit series, was incarcerated at the Federal Medical Center in Lexington, Kentucky, last August -- and the "Chrisley Knows Best" star checked in there Tuesday.

It's a minimum security satellite camp -- it won't be confused with a SuperMax -- but that doesn't mean Julie and Jerry get to socialize in the yard. For obvious reasons, we're told the feds keep male and female inmates in separate sections of the facility.

As we reported, Julie was convicted last June for…