The "Umbrella" singer, who was signed by the hip-hop mogul to Def Jam Records in 2004, admits she constantly goes to Jay-Z for professional advice but also quizzes him about her personal problems.
Rihanna, 19, said: "Jay-Z is just an amazing mentor."
"I always go to him if I have a work-related problem, but I ask him about problems in my personal life too."
"He's incredible. I trust him completely."
The Barbados-born star has also quashed rumors she is planning to quit pop to be an actress.
Although Rihanna - who has appeared in hit US TV shows "Veronica Mars," "Entourage" and "CSI: NY" - enjoys acting but has no intention of hanging up her microphone.
She explained: "I love acting and definitely want to do more in the future. But singing has always been, and always will be, my first passion."
