Ryan Seacrest and Julianne Hough
07/12/2011 AT 06:00 AM EDT
Julianne Hough frolicked on Miami Beach
– not with beau Ryan Seacrest
, but with her mom, Marriann, and her costar, Diego Boneta
. The actress, who's filming Rock of Ages in Florida
, enjoyed her downtime, swimming in the ocean and in her condo pool. "Julianne and her mom were having a blast, skipping through the waves, holding hands and enjoying the beautiful summer day," says a source.