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.

A.J. McLean went from a Backstreet Boy to a married man Saturday night in Beverly Hills.

The singer wed his longtime girlfriend Rochelle Kandis in an elegant ceremony at the Beverly Hills Hotel.

Kathy Griffin was there, as was New Kids on the Block singer Joey McIntyre and McLean's BSB bandmates Kevin Richardson, Howie Dorough and Nick Carter.

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A.J. asked Rochelle to marry him almost two years ago with a surprise proposal while she was in the audience during one of his live shows.

She obviously said yes.  Congratulations to the bride and groom!

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Aaron Carter checked into rehab but in this shocking photo obtained by RadarOnline.com it’s clear the young pop star was grappling with addiction long before he entered treatment.

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The photo, taken in 2003, shows a topless Carter lighting a yellow pipe.

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As RadarOnline.com reported the 23-year-old former Dancing With The Stars contestant entered rehab “to heal some emotional and spiritual issues he was dealing with,” his rep said.

On February 21, 2008 Carter was arrested in Texas when authorities found marijuana in his car after a routine traffic stop.

Aaron Carter has a brand new look and he's almost unrecognizable from the pop star who made young girls swoon in the late 90s. Attempting a music comeback, Carter Tweeted an amazing picture of himself that you see here on RadarOnline.com.

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Aaron, younger brother of Backstreet Boy Nick Carter, had a successful pop and hip hop career in his mid-teens and also made several acting appearances.

He went the reality route with an E! series about his family, competed on Dancing with the Stars in 2009, and was briefly a Lindsay Lohan boyfriend....and he weight-lifted through it all.

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But he wants to be at the top of the charts again and is working with the legendary manager/producer Johnny Wright -- he's Justin Timberlake's music manager -- on some new sounds.

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He Tweeted his muscle-bound pic with the note, "I've been at Johnny Wright's compound working on my mind, music and body for a new album release."

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