Jessica Simpson and Billy Corgan - who has refused to confirm speculation they are dating - are reportedly obsessed with playing chess against one another.
The singer-and-actress - who has refused to confirm reports she is dating the Smashing Pumpkins singer - has become addicted to the board game after he taught her how to play and now they like to take on each other on a regular basis.
A source said: "He taught her how to play and was surprised at how quickly she got the hang of it, but she is yet to beat him."
As well as chess, Billy has also been teaching Jessica to play the guitar.
The source added to National Enquirer magazine: "Billy likes to share his hobbies with his friends."
The 43-year-old rocker recently revealed he "loves" the 29-year-old beauty but refused to be drawn on gossip they are dating.
He said: "If I go, 'Oh, we're just friends,' then it's like, 'Did they go out, did he dump her or she dump him, what happened?' It has nothing to do with any of that. Sometimes people just like being around each other, and good things come out of that.
"My goal in life is to love whoever I think is worth loving, and I think if people knew her like I knew her, they would love her like I do. It's really simple."