Jessica Simpson and boyfriend John Mayer

Jessica Simpson's dad "loves" her new boyfriend John Mayer.The singer-and-actress, who has been dating the musician since last August, has won her father Joe's approval with her latest relationship. Joe told People magazine: "If Jessica is in love, I love the things she is in love with."I want her to be happy. I'm always a fan of John. I love him - he's got great music."Jessica's father hasn't always approved of her previous lovers. He warned his daughter marrying Nick Lachey could ruin her career. Jessica, whose divorce from former 98 Degrees singer Nick was finalised last June, said: "Everybody thought, including my father, that my marriage to Nick would kill my career."Joe is convinced Jessica will be happier with John because they have a different fan base and are equally famous. He explained: "I think the beautiful thing is that he and Jessica don't do the same thing. He's a legend already. There is no competition. He's a guitarist - that's his thing. Jessica is a singer. She doesn't play guitar, so there's no competition."Jessica joined John on tour in Australia last month, and is currently in France attending the Cannes Film Festival.