Bradley Cooper and his 7-year-old daughter, Lea, attended the star-studded pool party held at Taylor Swift’s $17 million Rhode Island mansion

Duty of a father.

Bradley Cooper took his daughter Lea De Seine to a star-studded pool party held at Taylor Swift’s $17 million Rhode Island mansion on Saturday.

The “Hangover” actor, 49, and his 7-year-old son were spotted standing on the balcony of the “Bad Blood” singer’s expensive vacation home, according to photos obtained by the Daily Mail.

Cooper, who shares a daughter with his ex-wife Irina Shayk, flashed a big smile as he looked at Lee, who had her hands raised to her dad’s chest.

The “Maestro” star dressed simply for the occasion, wearing a short-sleeved black shirt and holding a black hat in his hand.

It’s unclear whether Cooper’s girlfriend, model Gigi Hadid, was at the party.

The “A Star Is Born” actor was one of several A-listers at the 11,000-square-foot estate purchased by Swift in 2013.

Also in attendance were the Grammy winner’s boyfriend Travis Kelsey, Patrick and Brittany Mahomes, and Swift’s friends Blake Lively and Ryan Reynolds.

According to photos obtained by Page Six, the billionaire pop star can be seen enjoying time on her balcony with the Kansas City Chiefs tight end, the team’s quarterback, and one of her two children.

Lively — who has been the center of drama surrounding her latest film, “It Ends With Us” — and her husband, Reynolds, 47, were spotted kissing before entering the mansion.

According to photos obtained by the Daily Mail , Travis’ brother Jason Kelsey and his wife Kylie Kelsey as well as their children were also in attendance at the closing summer festival.

The pool party comes just days after Swift concluded the European leg of her Eras Tour in London.

The “Cruel Summer” singer and Travis, both 34, were able to spend time together in Rhode Island thanks to the NFL star’s “long weekend vacation.”

,[The Chiefs] I’m on leave yesterday, today and tomorrow, but he won’t be staying for long. [He and Patrick] “I have to be back tomorrow night for a Monday morning meeting with the team,” a source close to Travis told Page Six exclusively.

The Chiefs’ first game will be against the Baltimore Ravens on September 5 in Kansas City, Missouri.