Bradley Cooper and Gigi Hadid’s relationship is continuing down a solid path.

A source tells PEOPLE that the couple are in “a full-blown relationship,” and that Hadid, 29, “is very happy” with Cooper, 49.

“They are both busy but manage to spend time together and are enjoying each other,” the source adds. “I wasn’t sure this was anything other than a casual fling when it started, but it has grown more serious.”

According to the source, the supermodel and Maestro actor-director have fun together and like a lot of the same people, and Hadid admired Cooper and had a crush on him before they dated. “They have a good solid social life and are really happy,” the source adds.

Another insider tells PEOPLE of Hadid and Cooper balancing their careers, family and relationship, “Considering how busy they both are with work and family, they have managed to keep this alive and are going strong.”

“They had a solid start and it has built from there,” the insider continues. “Each admires the success of the other, and they have kids in common.”

Cooper is dad to daughter Lea De Seine, 7, with ex Irina Shayk, while Hadid shares 3-year-old daughter Khai with ex Zayn Malik.

The romance between the actor and the model “has progressed more than” the insider “thought it would at first,” as well. “They talk about serious things and also joke a great deal,” the insider says. “They have made their relationship a priority in their otherwise busy lives.”

Cooper and Hadid were first seen together in October 2023, dining at Italian restaurant Via Carota in New York City’s West Village neighborhood.

Since then, the couple have been spotted numerous other times, including for a private dinner with Cooper’s mom after the 2024 Golden Globes in Los Angeles, where he was nominated for his role as both director and star of Maestro.

Cooper and Hadid also danced together in the audience during Stevie Nicks’ performance at the BottleRock Napa Valley food and music festival in May, as seen in a fan-posted video on X, holding hands and swaying to Fleetwood Mac’s “Dreams.”

Later at the festival, Cooper joined headliner Pearl Jam, led by frontman Eddie Vedder, onstage. The two duetted the song “Maybe It’s Time,” which Cooper recorded for his 2018 movie A Star is Born.