Secret Sphere is an Italian symphonic power metal band from Alessandria, formed by guitarist Aldo Lonobile in July 1997.

They caught the attention of major German heavy metal label Nuclear Blast, who would go on to release the band's third album, Scent of Human Desire, in May 2003.

In 2008, Secret Sphere released their fifth album, Sweet Blood Theory, on Avalon in Japan and the German label Dockyard 1 Records in Europe.

The album was based on the short story "The Vampyre", written by John William Polidori, as well as the atmospheres of Tim Burton's cinematographic work.

However, part way through recording, vocalist and founding member Roberto Ramon Messina left the band due to differences in musical direction.

[3] Michele Luppi, former vocalist of the Italian progressive power metal band Vision Divine, was recruited as Roberto's replacement, and the album, entitled Portrait of a Dying Heart, was released in November of that year on Scarlet Records.

Lifeblood was widely praised by reviewers who noted the band's ability to combine the classic power metal sound of their early years with the melodic rock leanings of their later output.