A grainy, barely audible, two-minute-long home video clip that seems to depict troubled [article id="1575921"]Grammy-nominated songstress Amy Winehouse[/article] smoking crack cocaine has surfaced online, elevating concerns about the state of the singer's health.

It remains unclear when and where the video -- which is being hosted at U.K. tabloid The Sun's Web site -- was shot. Several reports speculate that the footage must have been filmed in recent weeks because Winehouse is blond in the video; the singer ditched the brunet look last month. It also appears to have been filmed at Winehouse's London home; at one point, her wedding picture can be seen hanging on the wall in the background.

While reports circulated on Tuesday (January 22) that Winehouse had entered a rehab facility, the singer's U.S. publicist told MTV News that she had not.

"No, she did not enter rehab," the rep said. "She had an appointment with her doctor today and this is part of an ongoing treatment routine." She declined to comment on the video footage.

Winehouse's U.K. label, Island Records, issued a statement that reads: "We are deeply disappointed and upset by these latest revelations and are doing everything we can to offer Amy our full support in dealing with her problems."

According to The Sun, the clip on its site was edited down from the 19-minute-long original, which the paper says was shot on Friday. In the clip, Winehouse walks around her home wearing a dark tank top. She speaks to someone on her cell phone, as well as the person shooting the video. At one point, Winehouse proclaims, "I just took about six Valium." The video then shifts to the singer's bedroom, where she lights a glass pipe and inhales; the tabloid claims the pipe was a crack pipe.

The video is just the latest in a long spate of bad publicity for the embattled artist, and comes on the heels of what was a breakout year for Winehouse. Late last year, Winehouse received six nominations for next month's Grammy Awards, including for Record of the Year and Song of the Year for "Rehab" and Best Album for Back to Black.

Over the course of the last year, however, Winehouse has become a household name not only because of Back to Black's successes but also because of her brushes with the law.

In October, she was fined after marijuana was found in her hotel room in the Norwegian city of Bergen. She also [article id="1575117"]called off a previous series of shows and appearances,[/article] which reportedly allowed the singer to seek treatment for drug addiction.

On December 18, Winehouse was [article id="1576683"]arrested for questioning[/article] in connection with a court case in which her husband, Blake Fielder-Civil, was charged with perverting the course of justice following a bar fight; she voluntarily went to a police station in East London at a pre-arranged time and was released with no charges. Fielder-Civil is currently in prison as he awaits the start of his trial.

Also in December, pictures were published showing Winehouse with the residue of an unidentified white powder on her nose, and later that month, pictures surfaced of a wandering Winehouse, walking the streets of London barefoot, wearing only jeans and a bra.

Recent Winehouse performances have not been well-received, according to reports, with some shows drawing boos from those in attendance. In November, during what was her first concert since the arrest of her husband, Winehouse was reportedly crying, and "streams" of people walked out before the end, the BBC reported. In response to the chorus of boos that heckled her, Winehouse warned, "To them people booing, wait till my husband gets out of incarceration. And I mean that."

Winehouse is scheduled to perform with Mark Ronson during the upcoming Grammy Awards, which will take place February 10, although it has been reported that potential visa issues could prevent her from attending the ceremony.