Cardi B just posted the first public pictures of her newborn baby.

The photos, captioned with the date Nov. 4, have also raised speculation she could be engaged because of the huge rock on her finger. TMZ has learned, however, it is NOT an engagement ring.

As you know … the newborn baby boy marks her first baby NFL star Stefon Diggs.

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The new addition will join Cardi’s previous 3 children — Kulture, Blossom, and Wave — with ex Offset, and Stefon’s daughter, Nova, from a previous relationship.

We’re told Stefon, the New England Patriots star receiver, was with Cardi when their baby boy arrived.

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Cardi initially announced the birth last week in a social media post.

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She wrote … “My life has always been a combination of different chapters and different seasons. My last chapter was the beginning of a new season. Starting over is never easy but it’s been so worth it! I brought new music and a new album to the world! A new baby into my world, and one more reason to be the best version of me, one more reason to love me more than anything else or anyone else so I can continue giving my babies the love and life they deserve.”

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Cardi and Stefon started hooking up shortly after she split from Offset last year after a somewhat tumultuous 7 years together.