According to the Santa Barbara County Sheriff's Office ... the theft went down on July 4, and cops believe their residence was "targeted due to the victim’s celebrity status."
No word on the value of what was taken but cops say some of the stolen items include high-value jewelry and watches.
The Sheriff's Office says it's working with other law enforcement agencies, as part of an extensive investigation, to see if this incident is connected to other recent celeb home burglaries.
It's unclear at this point if Portia and/or Ellen were home at the time of the break-in.
Ellen purchased the massive 8,188-square-foot, Balinese-style home in early 2019 for a whopping $27 million ... and it's easy to see why it comes with that price tag.
Cops offered up some free advice to other residents in the area -- which includes several celebrity estates -- to avoid social media posts about being on vacation and leaving lights and TV on while away.