There aren't many professional singers who can hold their own with MARTINA MCBRIDE.  So how awesome was it when Martina let a 13-year-old join her on stage for a song . . . and the girl totally nailed it.

Her name is Kate Falcon and she was at Martina's show last Friday in Nashville.  Martina invited her up to the stage and they did Martina's song "Anyway". 

They trade verses early on and then Martina was so impressed she turned it over to the girl and actually took a seat.

(--Here's the video of Martina and Kate performing "Anyway".  The song starts at the 0:47 mark . . . Kate joins in 1:17.  Martina sits down at the 2:50 mark.)