Check out this pic of the WWE superstar doing the classic bump cradle during a walk Wednesday afternoon in Los Angeles. She was on her way to visit a friend, and it ain't hard to figure out what they'll be discussing.

It's pretty crazy ... Nikki and her twin, Brie Bella, are both pregnant, and their due dates are only a week and a half apart. That's some serious womb symmetry!!!

As we reported ... Nikki got engaged back in November to her former "Dancing With The Stars" partner, Artem Chigvintsev, and she says they weren't even trying to get pregnant.

Brie says she was also shocked by her second pregnancy with husband -- and fellow WWE superstar -- Daniel Bryan after resigning herself to being a mother of one.

No word on sex or baby names yet. We sense a synchronized gender reveal in the near future. Congrats!!!