FORMER first daughter Jenna Bush’s “wild child” days are long gone – as The ENQUIRER las learned she and her investment banker hubby are expecting their first child! PLUS: her wild, wild past!

The bubbly 31-year-old, now a correspondent on NBC’s “Today” show, was spotted with a vis­ible baby bump while shopping at an upscale New York City market.

“Jenna’s got a baby onboard,” an eyewit­ness revealed. “It appears there’s a little ‘Bushie’ on the way. She was showing a bulging baby bump when I saw her shop­ping in a T-shirt and leggings at the Whole Foods store in the TriBeca section of New York on Dec. 4.”

The stork news is sure to delight Jenna’s parents, former president George W. Bush and wife Laura.

“I don’t have any children,” Jenna – who married Henry C. Hager in May 2008 – said at an event in 2011.

“I just have a cat, to my parents’ dismay. My dad saw my husband’s boss at a conference, and he said to stop paying my husband until we produce children.”

The blissful domestic life is a far cry from Jenna and her twin sister Barbara’s wild-child behavior during their father’s first term in office, when they made headlines for underage drinking arrests.

In May 2001, authorities busted the then-19-year-old college students for using a fake ID to buy margaritas at a Mexican restaurant in Austin, Texas. A month before that, Jenna was charged with being a minor in possession of alcohol at a bar near the University of Texas campus.

In her second arrest, Jenna was fined $500 for trying to use a false ID. She also lost her driver’s license for 30 days and had to do community service and attend an alcohol-awareness class.

Now Jenna – who recently signed on to write a column for “Southern Living” magazine – is hoping her pregnancy will en­courage her sister to consider starting a family.

As The ENQUIRER has reported, Barbara has been quietly dating Panama-born graffiti artist Miky Fa­brega, 37, for the past two years. He favors painting in his under­wear and openly dissed her daddy when he was in the White House.

“Jenna would like nothing more than for Barbara to tie the knot soon and have a baby, hopefully in that order,” said an insider. “But it’s not mandatory. After all, Jenna isn’t as conservative in her views as her folks.

“Since the sisters live just a subway stop away from one another, it would be a snap to arrange spur-of-the-moment play dates. Barbara also has a cat, so they could have kitty play dates, too!”