The pair have had a friendship and artistic relationship going back many years. Amos has referenced Gaiman on a number of her songs, while he has written stories for her tour books and her 2001 album Strange Little Girls.
Asked how she felt about HBO's upcoming adaptation of Gaiman's American Gods, Amos told Digital Spy: "Well, I'm a bit biased towards that one because it was written partly at the beach house in Florida, and he is just one of my favourite people in the universe.
"He's a spiritual brother to me and has always been. We're really close friends and yet I have great respect for his talent. So I'm thrilled.
"I love all his work, but American Gods was something I remember reading before it came out and I thought this is one of those stories that people will re-read for a long, long time to come."
She added that her daughter Natashya was a big fan of Gaiman's episode of Doctor Who, 'The Doctor's Wife', which aired earlier this year.
"Natashya doesn't miss an episode," Amos said. "She knows them all. She showed it to me and of course I thought it was great.
"She said, 'Look, Uncle Neil's episode was the best. They should have had him write the whole series this year because his portrait of the TARDIS, you can't beat that'."
> Read our full interview with Tori Amos
Watch the BBC America trailer for 'The Doctor's Wife' below: