Sir Christopher Lee has completed his second rock record – and the good news is that it's "100% heavy metal".

The veteran actor, best known as Dracula in the Hammer horror films and Saruman in the Lord of the Rings trilogy, will release Charlemagne: The Omens of Death, on 27 May, his 91st birthday. The album, which was recorded with Judas Priest guitarist Richie Faulkner, is the followup to 2010's Charlemagne: By the Sword and the Cross.

"The first Charlemagne album is metal, of course, but what I sang was more symphonic," Lee said. "Now on the second one, The Omens of Death, it is 100% heavy metal. I've done my bits and pieces, and they are heavy metal. I'm not screaming or anything like that, but it is definitely heavy metal."

Faulkner added: "Most of the songs were already there, but they needed riffs, drum parts and musical parts that reflected what the guys wanted – which was a metal record with an aim to be played live by a band. Some of the tracks didn't have any music at all and were just Sir Christopher singing his melodies. I remember how surreal it was sitting in my place at the time with Saruman blasting out over the speakers! I've no idea what the neighbours thought."

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Once Faulkner left the project in order to join Judas Priest as KK Downing's successor, the position of axeman was taken over by Guitar Idol 2009 runner-up Hedras Ramos.

"It was a lot of fun for me," Ramos said. "I just had to listen a lot to Iron Maiden, Judas Priest and all those guys – the old-school heavy metal – to absorb the sound and the flavour of this music. Composing the music for The Devil's Advocate and The Ultimate Sacrifice was quite a trip and tons of fun, because I was given total freedom to add my personal guitar approach to the album. This is a great album for all metal, fantasy and Christopher Lee fans!"

Charlemagne, also known as Charles the Great, was the first holy Roman emperor, in the eighth century, and the first emperor in western Europe since the collapse of the western Roman empire three centuries earlier.

Lee was given the Spirit of Metal prize at the 2010 Metal Hammer Golden God awards for By the Sword and the Cross.