Eniko announced the big news early Wednesday morning, saying Kaori Mai Hart was born Tuesday. Eniko's post said she'd spent 9 months preparing to fall in love for a lifetime. She captioned it with, "a little bit of heaven sent down to earth..welcome to the world baby girl..we couldn't love you more.."

As we reported ... Kevin and Eniko announced back in March they were expecting their second child together. Eniko referenced the early days of coronavirus quarantines, saying ... "BABY #2 in the midst of all of this we're counting our blessings and couldn't be more grateful!! soon to be a family of 6!"

As you know ... Kevin has 2 kids with his ex-wife, Torrei -- 15-year-old daughter Heaven and 12-year-old son Hendrix. Kevin and Eniko got married in 2016. their first child together is a 2-year-old son, Kenzo.

Get ready for a loud house, Kev. Also ... congrats!!!