Rose, 29, posted a picture of her makeover on a social networking site while soaking up the sunshine on a day out at the beach on November 4, reported Us magazine.
She clad her ever-growing bump in a cute and girly smock-style denim printed dress, which drew attention to her pregnancy figure.
The couple announced their baby news at the MTV Video Music Awards on September 6.
She had recently said that she is planning to have an all-natural water birth without the help of medical aid, and the couple confirmed they are keen to resume planning their wedding after their son is born.