The Queen of Pop took to the website to post the snap, which was taken during Bey's Mrs. Carter Show World Tour show, held at the Brooklyn's Barclays Center in New York last night (Thursday 09 December).
In the image, the XO singer can be seen planting a smacker on the eight year old's head during her performance.
Madge accompanied the pic with the caption: 'Mercy James gets a big fat one from the Queen. B!
She later added: 'Mrs. Carter crushes the BK (Brooklyn) with her bad ass show! Girls run the world!