NEW YORK (AP) — Demi Lovato celebrated six years of sobriety at a concert in New York with tour mate DJ Khaled, whose powerful brought the pop star to tears. Lovato performed Friday night at the Barclays Center in Brooklyn, telling the audience that March 15 was a proud day for her. DJ Khaled played the role of preacher, life coach and best friend as he offered words of inspiration, motivation and admiration to Lovato, who has been open about her issues with drugs and alcohol.