Us broke news back in October that Murray, 32, and the Australian actress, 33, were an item. That same month, they debuted as a couple at the Lucky Brand Flagship Store opening event in Beverly Hills, Calif.
"They [were] very touchy with their arms around each other and holding hands," an onlooker told Us at the time. "They are definitely head over heels."
Murray and the Matador star first met on set of the film Left Behind, which is due to hit theaters this October. "I am a lucky lucky man. Blessed 2 feel the way I do with @NickyWhelan!" the One Tree Hill alum tweeted after going public. "I hope each of u feels the same in ur world!"
On Feb. 3, he continued the positivity. "If you love big & are loved big then happiness is Urs. Always. Embrace it. Enjoy it," he wrote. "The rest is all smoke and mirrors. Uve won. #GodisGood."
Murray was previously married to former One Tree Hill costar Sophia Bush. The Chicago P.D. actress annulled the marriage five months after their April 2005 nuptials and was granted a divorce. Murray ended his seven-year engagement to fiancee Kenzie Dalton in September 2013.
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