JJ Watt's son is adjusting well to his new role as big brother. The retired NFL player, 36, shared an adorable snap on Instagram of his son Koa, 2, kissing his baby sibling Niko on the forehead. In the photo, Watt had the newborn, whom he and his wife Kealia Ohai Watt welcomed on June 14, resting on his legs in a blue onesie in their home nursery. "Nothing better," the proud dad simply captioned the photo. Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer​​, from celebrity news to compelling human interest stories. Watt and his wife, 33, announced the happy news of their baby's arrival in a joint Instagram post on June 25. In one sweet photo, the family of four poses together for their first social media photo. Kealia can be seen holding their new little one, while Watt puts an arm around his wife and holds Koa. The happy couple also included a snap of Koa holding his new sibling, as well as a shot of the former athlete holding his new baby. "Overcome with joy and gratitude," the couple wrote in their joint caption. "Niko Benjamin Watt. 6.14.25. ❤️💙." They previously announced they were expanding their family in a February Instagram post, showing the then-family of three and their two dogs. "Can’t wait to welcome new love into our lives. ❤️💙," their joint caption read at the time. The post featured photos of Koa kissing the former Chicago Red Stars player's growing baby bump as she looked down and smiled, while Watt proudly stood nearby. Their dogs were front and center, watching them enjoy the moment. In another photo, the former pro soccer player smiled for the camera and held her bump as Watt held and smiled at Koa. A fun, candid image of Watt, Kealia and Koa rounded out the carousel. The PEOPLE App is now available in the Apple App Store! Download it now for the most binge-worthy celeb content, exclusive video clips, astrology updates and more! Speaking with PEOPLE in January 2024, Watt shared that his 2-year-old son is already following in his parents' footsteps when it comes to his love of sports. "He's really loving sports," he said. "He's got his own little basketball hoop and he loves to put the ball in the hoop. He's got some mini hockey sticks and he's finally learning how to use two hands on the hockey stick, which is great." Watt added that he and his wife, who are both athletes, wouldn't be against Koa taking on a sport of his choosing. "We obviously love sports because of everything that they teach kids," he continued. "They teach discipline, they teach hard work, they teach teamwork. They teach how to deal with winning and losing, how to deal with adversity." "We've experienced that our whole lives, so we're really looking forward to him participating, as long as he wants to, and it seems so far like he's interested," he added.