U.S. actor Kellan Lutz and Australian actress Sharni Vinson have ended their 2-year romance, UsMagazine.com reported. No reason was given for the breakup. The former couple met during an audition for the dance movie \"Step Up 3D.\" Vinson landed a role but Lutz didn\'t get the job. He went on to appear in the \"Twilight\" film franchise.