A birth certificate obtained by PEOPLE reveals the couple’s firstborn celebrates his first birthday on May 13

Rihanna and A$AP Rocky are celebrating their baby boy!

The pregnant singer, 35, and her partner, 34, celebrated their son RZA Athelston on his birthday with a carousel of various family photos.

A$AP started the post with a cute picture of RZA crawling on a blanket next to the superstar artist as she kissed A$AP Rocky on the cheek.

He also shared multiple other photos of the three posing for the cameras and acting silly in the mirror.

He then posted several snaps of him bonding with his son, including a shot of him shaving with

RZA in his arms and even a video where the proud father holds his son up and dances him around.

His final slide of the post showed a video of Wu Tang Clan founding member Ol’ Dirty Bastard at an award show saying that “Wu Tang Clan is for the children.”

He echoed the sentiment in his caption for the post on Instagram, writing: “WU TANG IZ 4 DA CHUREN 🤲” HAPPY 1st BIRTHDAY TO MY 1st BORN . RZA❤️.”

The baby boy’s unique moniker was confirmed by the birth certificate obtained by PEOPLE earlier this week.

The name pays homage to the leader of the Wu-Tang Clan, producer and rapper RZA (pronounced “Rizza”), whose real name is Robert Fitzgerald Diggs.

The name reveal comes almost a year after the “Diamonds” singer and Rocky welcomed their first baby together and just a few months after

Rihanna surprised the world with a second pregnancy during her Super Bowl halftime show.

“She loves being a mom so this is where her mind is at the moment,” a source told PEOPLE in February. “She is the happiest she has ever been.”

Speaking to new motherhood in the March issue of British Vogue, Rihanna said her first few months have been “legendary” with the infant.

“It’s everything. You really don’t remember life before, that’s the craziest thing ever,” she said.

“You literally try to remember it – and there are photos of my life before – but the feeling, the desires, the things that you enjoy, everything

You just don’t identify with it because you don’t even allow yourself mentally to get that far, because…. Because it doesn’t matter.”