MIAMI -- Talk about a picture being worth a thousand words.

A standard family snapshot at the Miami Zoo turned into a stunner of a photo-op.

Alex Hawker, 7,  had been posing for a picture in front of the lion's den when he got a surprise and an unexpected photo partner. 

"It jumped on the glass, and I said, 'What was that?' Then I looked. It was a lion."

Sean Hawker captured the picture of his son's close encounter with the big cat.   In fact, it looks just like the lion is hamming it up for the camera.

He says it was sheer luck -- a "one in a billion shot."

CNN