The 'So You Think You Can Dance' presenter - who married the Northern Irish comedian in surprise ceremony in Rome at the end of last month - was spotted taking in the romantic sights around Burano Island on the Venetian Lagoon and enjoying a boat trip under the Bridge of Sighs with her new husband over the weekend.
An onlooker told the Daily Mirror: "It was ¬really lovely to see two people who are so obviously madly in love.
"When they'd finished the trip, Patrick leaped out and offered his hand to help her ashore.
"There aren't many more romantic places than Venice in the autumn."
The 35-year-old 'So You Think You Can Dance' presenter tied the knot in a stunning ruffled dress with flowers in her hair in front of a small gathering of family and friends on September 30 and her best friend Edith Bowman acted as bridesmaid.
Patrick (41) denied rumors he had popped the question to Cat in August but speculation continued to swirl after she was spotted wearing a ring on her engagement finger at a party before the 'Primetime Emmy Awards' just one week before their low-key wedding.
The couple - who live together in a £1.7 million Beverly Hills mansion - confirmed their relationship in May after more than a decade of friendship but were first romantically linked in February after they holidayed together.