According to sources, Bieber and Sofia, who made their relationship public in August, were never all that serious to begin with despite vacationing together in Mexico for her 18th birthday, reports tmz.com.

They were last photographed together in Los Angeles on August 26 and haven't been seen together in public since then. 

As to sources, they haven't been talking much lately. 

On Sunday, September 18, Sofia stepped out alone at an event. She was also spotted at Treats! Magazine party over the weekend, enjoying a night out with her friends. Bieber, meanwhile, is ready to date other girls, according to sources.