At 19 months, Prince Jacques and Princess Gabriella joined their parents for a pool party

Credit: Gaetan Luci/Courtesy Prince's Palace

Monaco’s royal twins are growing up!

Prince Jacques and Princess Gabriella, 19 months, attended a garden party on July 22 in advance of Saturday’s glamorous Red Cross Gala – and yes, they made quite a splash. (Even if their parents weren’t quite dressed to get wet!)

Want to keep up with the latest royals coverage? Click here to subscribe to the Royals Newsletter.

The poolside event, a cocktail party in the palace gardens at which South African-raised Princess Charlene was named patron of the South African Red Cross, took a family turn when the royal mom and her husband Prince Albert brought their twins for a surprise visit.

In photos taken by veteran palace photographer Gaetan Luci, the twins can be seen wading into royal diplomacy – charming the attendees, including the head of the South African Red Cross, Constance Motshumi, and Derick Naidoo, there to announce new ties between the Monégasque and South African Red Cross associations.

The afternoon was a true family day, with Charlene’s father Mike Wittstock, her brother Gareth and his wife Roisin all attending the reception. The Cenestra Male Choir (a South African troupe that performed at Mike’s surprise birthday in February), were on hand to entertain guests.

Charlene, who has said that she wants her children to know and experience their African culture, added a notable fashion touch – the twins wore zebra- and Bantu-inspired footwear before going for a dip in the palace garden pool, which their late grandmother, Princess Grace, installed in the 1950s.

Princess Charlene of Monaco Wins our Most Glam Royal of the Week!

The twins have been hitting the pool at their country home, Roc Agel, twice daily this summer, Prince Albert recently told PEOPLE.

So far, Gabriella has herself the more adventurous swimmer so far, says her dad: “She likes putting her head underwater more than Jacques does!”