A Taylor Swift Super Bowl halftime show is gaining steam. In the days since the pop star joined boyfriend Travis Kelce’s “New Heights” podcast, the rumor mill has churned about a potential on-stage appearance at Levi’s Stadium during the Big Game. And prediction markets have followed.

Swift spoke about her love of numerology during the show, and fans linked her comment about having thoughts of sourdough “60 percent of the time” to next year’s Super Bowl since it is the NFL’s 60th ever. The game will also take place in Levi’s Stadium, home to the San Francisco 49ers whose mascot is notably Sourdough Sam.