Prinz, 23, was in New York City on Tuesday to host MTV's Total Request Live. The actor is known best for roles in films such as I Know What You Did Last Summer and She's All That.
McCullough, 21, left her regular duties on General Hospital in 1998 to attend college.
Astrology buffs would have pinned this as a healthy relationship --- both are Pisces. McCullough's birthday is March 5th and Prinze's is March 8th.
There's been no comment from either camp on the reported split.