Despite a singing and performing career that has spanned six decades, Engelbert Humperdinck describes Sept. 30, 2014, as the best day of his life.

“That’s the day I released my new duets album, ‘Engelbert Calling,’” the British singer, who was born Arnold Dorsey in India, explains to ‘Closer.’

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Engelbert on ‘The Engelbert Humperdinck Show’ in 1969.

“I was nervous and happy that it was finally released, because I’d had so many fans asking me when the album would be available. It was a two-year labor of love,” he adds.

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At 78, the crooner has seen it all, but he says that recording his latest CD was a new experience for him because all of his guest stars made it special.

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Engelbert performing in February 2014.

“It’s the only duets album I’ve ever done,” he explains. “I worked with so many legendary people on it. I got to record with Elton John, Olivia Newton-John, Gene Simmons, Wynonna Judd and Kenny Rogers. When I called them and asked about doing it, everybody was so receptive!”