Derek Fisher's making sure Gloria Govan always looks like a million bucks even in sweatpants because that's about how much her knuckle-sized engagement ring's worth ... TMZ has learned.
We're told the ex-NBA star designed the 7.5 carat diamond ring, which he scooped up from L.A.-based jeweler Bony Levy. A rock that size normally goes for just north of $1 mil ... according to our fancy jewelry sources.
The engagement had been a long time coming.