Real estate sources tell TMZ ... the Beverly Hills property, which sits on almost 2 acres of land, is now selling for a whopping $48 million and it's been completely transformed since the KISS frontman had the keys to this palace.

You'll recall, Gene sold the home to Max Nobel of Nobel Development Group back in 2021 for a mere $16 million. We're told the entire property underwent a massive 18-month makeover before returning to the market ... so much so, it's considered a brand-new property.

The new place is completely unrecognizable and was stripped to its studs ... with Nobel L.A. redoing every inch of the 79,948-sq-ft lot and estate that features 7 bedrooms and 11 bathrooms.

It comes with enough parking for up to 30 cars! There's a 3-car garage attached to the main house and a separate 10-car garage with the option for lifts that can accommodate 20 cars -- it all sits where Gene used to have a tennis court.

We're told there's still room for a pickleball court if the new owners are interested in installing it. The property also includes a gorgeous new 60x20 swimming pool, a movie theater and an outdoor BBQ area with a 30-guest dining space ... lots of room for entertaining!

Buzz around the city is this is one of the most incredible properties in California and despite it being massive, it has the type of privacy one can only dream of having in Bev Hills.