Global win for Back To Black.

Winehouse gives Universal the UK's biggest-selling album worldwide in 2007, but recent events put Grammy appearance in question

Amy Winehouse's Back To Black has been named as the UK's top seller globally of 2007, but the singer now faces an anxious wait to learn if she will be allowed into the States for the Grammy Awards.

Exclusive Music Week research reveals the Island-issued album sold 3.4m units overseas last year to finish as the most successful album by a UK- signed act. Her record company Universal is hoping that figure could swell significantly over the next few weeks if she is able to perform at the 50th annual music event where she is competing for six prizes, including the key record, song and album of the year categories.

That will all depend on the outcome of her case being heard tomorrow (Tuesday) by the US immigration authorities, who will consider whether to allow her in, despite a conviction in Norway last October for drug possession. The decision will come against the backdrop of front-page news last week of her being captured on film in her home apparently taking drugs, while she has subsequently entered a rehabilitation clinic.

The Grammy nominations announced in December capped a remarkable year internationally for Winehouse, whose second album last March became the first debut by a UK female soloist in US albums chart history to begin life in the Top 10. In what was obviously a difficult year personally for the artist, Back To Black has gone on to sell around 1.5m units in the States, while the album has clocked up significant sales in other territories, including 600,000 in France and 350,000 in Germany as it topped the chart in both markets.

"Everyone is extremely happy with the amount of records we've sold and a lot of it has been down to some amazing marketing opportunities in the market when the artist wasn't available," says Universal Music International VP Hassan Choudhury. "There's no getting away from the fact all the coverage has kept her profile at the highest level."

Back To Black followed what was, in Frank, a critically-acclaimed but moderately-selling debut, but Choudhury says when the record company heard lead single Rehab in a marketing meeting for the first time "everyone felt straight away this was a crossover record". "The bottom line is she's made a truly sensational record and she's an exceptional artist," he says.