Two yolks in one egg? Anyone seen this before?

Makeup artist, Banke Meshida found two yolks in one egg few days ago. Has anyone seen this before? She wrote:

“Hmmm on a happier note, I found 2yolks in my egg just now #twins or is it a case of #GMO egg???? Lol #doubleyolkeggs So if it hatched will 2 chicks stagger out?”