Royal Baby Alert! Monaco’s Pierre Casiraghi and Beatrice Borromeo Expecting Second Child

There’s a baby on a approach for Monaco’s stately family!

With Prince Albert on a state revisit to South America, all eyes during a Bal de la Rose incited to Princess Caroline’s family opening to a 64th annual soirée on Saturday.

Looking radiant, daughter-in-law Beatrice Borromeo, 32, wore a black velvet Alberta Ferretti Empire-style robe as she cradled her baby bump. Soon-to-be father of dual Pierre Casiraghi, 30, who is now 7th in line of Monaco’s succession, dressed in a black tuxedo.

Sources during a Bal tell PEOPLE Beatrice is due in May.

Pierre Casiraghi and Beatrice Borromeo

The couple, who married in dual intemperate ceremonies in Summer 2015, already have one-year-old son Stefano.

Just final year during a same glamorous Monte Carlo event, Beatrice and Pierre, who met in college and have been together given 2008, done their first post-baby open appearance together.

The child will be Caroline’s fifth grandchild. Prince Albert has formerly told PEOPLE how his sister Caroline was looking brazen to a enlargement of her stately family.

“She’s a unequivocally good mother, and substantially an even improved grandmother now if that’s possible,” Albert pronounced in Jan 2017. “She unequivocally lifted her kids well. Without a father for many years, that’s important. I’m impossibly unapproachable of her children and to have them spin out as they have — that’s a reverence to her.”

Also during this year’s Bal de la Rose, Pierre’s sister Charlotte Casiraghi reliable her rendezvous to Dimitri Rassam by wearing a solid ring on her left hand.