Talk show queen Ellen DeGeneres just bought a REALLY nice present for her wife, Portia De Rossi ... a Malibu beach house!

DeGeneres signed on the dotted line Friday, for the purchase of Brad Pitt's $12-million estate in north Malibu.

The property is perched above a beach with private access and includes a pool and tennis court.

X17online reported Ellen was getting close to a deal for the luxury pad last month. And a few weeks later, we spotted Brad at the home, packing up some of his personal items in preparation for turning over the keys to DeGeneres.

Merry Christmas, Portia!