Ex-NBA star Gilbert Arenas is firing back at his estranged fiancee Laura Govan -- claiming her $1 MILLION engagement ring was A TOTAL KNOCKOFF!
TMZ Sports broke the story ... Laura is suing Arenas -- claiming he kicked her out of their L.A. mansion and then "forcefully took" her $1 million diamond ring, which she claims he sold.
But now, Arenas is finally breaking his silence ... calling B.S. on Govan ... and saying there's no way he would've "forcefully" taken her bling because she was rocking a FAKE.
"When u have a million dollar ring made you also have a fake one made JUST in case sh*t doesn't workout," Arenas posted on Instagram.
"Lets say sh*t didn't workout and she has the fake one...no need to forcefully take a ring back if its been sitting in a safe this whole time smdh."
"Why sell it when i can pass it down too my kids..PEOPLE my d*ck aint that big for everyone to be hanging on it lmaooo."
Arenas also says he's no deadbeat dad and didn't leave Govan and their four kids out in the cold -- saying HE'S the one who moved out of their Calabasas mansion.
These two are are clearly at war -- and unlike the diamond, this seems about as real as it gets.