London: Singers Marc Anthony and Jennifer Lopez will reportedly fight a custody battle over their three-year-old twins Max and Emme.

The former couple, who split in July after seven years of marriage, had an amicable arrangement where Lopez was the primary caretaker of kids.

According to sources, Anthony "hit the roof" when he saw pictures of Lopez's new boyfriend Casper Smart bonding with the children. He now wants joint custody.

"It caused a huge blow-up. (Now he is) going back on his word and saying he wants joint custody," a website quoted a source as saying.