Stephen and Hailey Baldwin.

The 'Boyfriend' hitmaker is said to have grown close to Hailey Baldwin in the wake of his split from on again-off again girlfriend Selena Gomez and believes the 18-year-old model is "different" to any other girls he's dated before.

A source told "Justin has a new muse and it's Hailey.

"She's different from the other girls Justin has been with. She's really fun, feisty, and could care less about Justin's fame and fortune."

The 20-year-old singer is described as being on the "rebound" from the brunette beauty and treated Hailey to an extravagant shopping trip to celebrate her recent birthday.

The source added: "Hailey's birthday was on November 22 so when she got to New York, Justin made sure to spoil her and treat her like a princess. He totally took care of her and took her shopping. He's definitely on the rebound from Selena."

Despite Justin's advances, Hailey - who is the daughter of Hollywood actor Stephen Baldwin - is said to be being "cautious" about her blossoming romance with the star.

An insider said: "Justin usually gets what he wants and he's trying to seal the deal with Hailey. But she's being a bit cautious. Hailey doesn't want to just be another girl on Justin's list. Right now, she's treating this relationship as a friendship."