Mike just shared the happy news with a clever photo of himself, Lauren and their dog in the kitchen ... with "Baby Sorrentino May 2021" written in flour on the counter.

The Sitch says, "We have a Baby Situation" ... and also included a sonogram of their little bundle of joy.

As we reported ... as soon as Mike got released from prison back in September 2019 after serving time for tax evasion, there was talk of getting busy with Lauren and starting a family.

The couple stated at the time, "We look forward to continuing our life as husband and wife and working on baby situations!" Turns out they weren't lying ... and even a pandemic couldn't stop them.

Mike and Lauren also upgraded their living situation in December by buying a 4-story mansion in Jersey for $1.8 million. The 7-bed, 10-bath pad features a ton of luxurious amenities, but more importantly ... it can easily accommodate a growing family.