Bill O'Reilly's show on Fox News has been won the cable demos (adult 25-54) every quarter since 2005.

But now Papa Bear has been toppled from his ratings perch.

And it was Megyn Kelly who did it. 

The Kelly file pulled in an averaged of 509,000 viewers in the demo, squeezing past O’Reilly’s 503,000.

Kelly was helped immensely when her show after the August 6 GOP debate. Millions of viewers stuck around after the debate and watched Kelly's show, which put her out in front of O'Reilly. 

Papa Bear still has bragging rights when it comes to total viewers as he won that race.