@oliviawilde / Instagram 1 / 11
@oliviawilde / Instagram 1 / 11

Splish-splash! Olivia Wilde knows how to have a little fun in the sun with her little one.

RELATED: Celebs' bodies after baby

The actress took to Instagram on June 10 to share a rare photo of her 13-month-old son, Otis, showing the two of them playing in a water exhibit.

"#BrooklynBridgePark #PleaseTouchTheArt #TheStokes," Olivia captioned the snap, appearing ecstatic about the fun moment with her little tyke. Otis, rocking a t-shirt for the band The Strokes, hence the hashtag, appears confused (or mesmerized) by the aquatics, but still adorable.

RELATED: Celebs embracing their flaws

The fact that Olivia even publicly showed a photo of her child is rare -- both she and her fiancé Jason Sudeikis have mainly kept Otis out of the public eye since his birth, only posting an image of their son every couple of months, although the proud mama did post a fun throwback photo of Otis two weeks ago.

She was also photographed while breastfeeding Otis for Glamour magazine back in August.

RELATED: Stars at Disneyland

Soon enough, Otis could have a little sister or brother, too. In March, Olivia told Shape Magazine that she can't wait to have another child.

"[Otis came] two weeks earlier than expected—an extreme adventure that is definitely not for the faint of heart," she said. "That day was wild, but weirdly I can't wait to do it again."