Sources confirmed the couple's relationship to Us Weekly days after the legendary singer, 68, and the Kill Bill actress, 53, were reportedly spotted kissing after grabbing a bite to eat in Westlake, Calif., Tuesday.
"She's a huge Neil fan," the insider said of Hannah. "They've known each other for years."
Young and Hannah, both known for they activism efforts, have protested several causes together including the construction of the Keystone XL pipeline in April.
News of Young's alleged new relationship comes two weeks after he filed for divorce from his wife and music collaborator of 36 years, Pegi Young.