Ryan Seacrest & Julianne Hough Make Waves in Miami

By Linda Marx and Alison Schwartz

06/27/2011 at 02:15 PM EDT

It's smooth sailing for Ryan Seacrest and Julianne Hough.

Taking a break from filming the Broadway-to-big screen adaptation of Rock of Ages in Miami, Hough, 22, hung on tight to her man, 36, on a jet ski ride Sunday.

"[Rock of Ages costar] Russell Brand had been raving about how much he loves to jet ski, so Julianne decided to get Ryan to try it with her," a source tells PEOPLE. "They looked really happy."

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The couple, who first stepped out together last summer, enjoyed the sunshine in the Sunshine State, squeezing in a dockside stroll – and some P.D.A. – before hitting the ocean.

Eager to spend quality time together, Seacrest and Hough skipped a dinner party at Gloria and Emilio Estefan's Star Island home Saturday night. Some of Hough's costars, including Tom Cruise (with wife Katie Holmes), Brand and Malin Akerman, attended the bash.

"Ryan and Julianne wanted to be alone," a source tells PEOPLE. Adds another: "The couple said they had spent so many days apart, they really wanted to chill."

Recently, Seacrest has been clocking in weekend trips to visit Hough.