The couple is said to have parted ways shortly before Christmas (25Dec12), which they originally intended to celebrate together.
The relationship is believed to have suffered as Cooper has been busy promoting his Oscar-tipped movie Silver Linings Playbook.
A source tells the New York Post's gossip column Page Six, "Zoe had planned to spend the holidays with Bradley and his family in Europe. They all were going to Paris, but things didn't work out between them. Zoe spent New Year's Eve with friends in Miami."
The pair originally dated for three months after bonding on the set of their drama The Words and split in March (12) before reuniting in September (12).