The 75-year-old singer, best known for his 1967 hit "Release Me," will be hoping to reverse a slump in fortunes for British acts at the annual sing-off.

"It's an absolute honor to be representing my country for this year's Eurovision Song Contest," the singer told the BBC.

"When the BBC approached me, it just felt right for me to be a part of an institution like Eurovision. I'm excited and raring to go and want the nation to get behind me!"

Humperdinck is the oldest Eurovision contestant and if he wins, will be the UK's first triumph since Katrina and the Waves 15 years ago.

The competition takes place on May 26 in Baku, Azerbaijan, where it has generated considerable excitement but also seen the country's human rights record come under closer international scrutiny.

In the latest example, Amnesty International said on Friday it hoped Humperdinck would draw attention to the issue of what it called "prisoners of conscience" being held in Azeri jails.

"There is a deep irony in the announcement," said Tim Hancock, campaigns director of Amnesty International UK, ahead of planned demonstrations in Azerbaijan over the weekend.

"Engelbert Humperdinck is famed for his song 'Please Release Me', yet, on the streets of Azerbaijan this Sunday protesters risk arrest by simply taking to the streets to display their discontent with the authorities."

Western governments and rights groups accuse President Ilham Aliyev, who succeeded his father in 2003, of rigging elections and clamping down on dissent, notably last year during a series of protests in the capital inspired by the Arab Spring.

The government says Azerbaijan, located on the Caspian Sea, enjoys full freedom of speech and has a thriving opposition press.

Humperdinck's song for the contest will be recorded in London, Los Angeles and Nashville and written by Martin Terefe and Sacha Skarbek.

Humperdinck, whose real name is Arnold Dorsey, has sold an estimated 150 million records worldwide during a 45 year career.

His participation could boost interest in this year's Eurovision Song Contest, widely derided in Britain as a celebration of kitsch but taken more seriously in many other European countries and watched by a television audience of more than 100 million people.

(Reporting by Mike Collett-White, editing by Paul Casciato)

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