United Kingdom, Oct. 13 -- Kelly Clarkson is "clearly so ticked off" by her row with a New York curiosity shop.

The 44-year-old Grammy Award-winning pop star has become embroiled in a very public spat with Art of Play in Brooklyn, with both sides having their say on social media after she compared her treatment to Julia Roberts' character in Pretty Woman.

A source told PEOPLE magazine: ""She's usually very private and public drama like this isn't her.

"She's clearly so ticked off that she couldn't keep quiet about it. Everyone is surprised by how much this whole thing has escalated."

The Since U Been Gone hitmaker had originally alleged that staff "looked at" her as if she "couldn't afford" their producers.

On Sunday (11.10.26) Art o...