A mere two days after his sister Leslie was found dead at 25, a brave Nick Carter took the stage before 700 fans at New York's Irving Plaza Thursday, and RadarOnline.com has video of his performance.

The singer took time out to pay homage to his late sibling: "I never thought I'd have to, but I'd like to dedicate this song to my sister," Nick, dressed in a spaceman suit, said somberly before launching into the ballad Falling Down.

Nick and Aaron Carter's sister Leslie Carter died on Tuesday of an apparent overdose, RadarOnline.com has learned.

According to a police report released on Thursday by officials in New York, the 25-year-old succumbed to what appears to be an overdose of depression medication.

An autopsy listed the cause of death as unknown, with the official report pending toxicology tests.

The autopsy of Nick and Aaron Carter’s sister, Leslie Carter, has been completed and the cause of death marked as unknown, pending toxicology reports, RadarOnline.com is reporting.

HollywoodLife.com spoke to Chautauqua County Coroner’s Office in upstate New York, Tuesday, who confirmed the autopsy had been finalized and that the singer’s body has been released to a local funeral home. They also report that Carter was visiting her father in Chautauqua County, New York, when she died -- Leslie lived in Canada, approximately an hour and a half drive away from her father’s home.

As RadarOnline.com previously reported, Leslie died Tuesday, age 25.

Nick and Aaron Carter's sister Leslie died Tuesday in Upstate New York. She was 25.

“Our family is grieving right now and it’s a private matter,” the family told Access Hollywood in a statement Tuesday. "We are deeply saddened for the loss of our beloved sister, daughter, and granddaughter, Leslie Carter.

“We request the utmost privacy during this difficult time.”

Leslie, a singer, married husband Mike in 2008, and gave birth to the pair's only child, daughter Alyssa Jane Ashton, on April 1, 2011.