Katy Perry is "incredibly embarrassed" she fell for John Mayer.
The Wide Awake singer was dumped by the renowned womaniser this week after dating for around two months and she has told friends she can't believe she allowed herself to get mucked around by him.
"Katy fell hook, line and sinker for John, so when he broke it off she was ultimately surprised and incredibly embarrassed," a source said.
"She's ashamed that she got played - it was the classic ladies man move, he added another notch on his bed post.
"He charmed Katy, got what he wanted and moved on.
"But Katy really liked John, she thought their relationship was the real deal, especially after he told her he wanted to put an end to his womanising reputation and was thinking of settling down."
Katy - who was previously married to funnyman Russell Brand - was warned off John by her friends and family as they didn't want her to get hurt.
"Family and friends did their best to dissuade Katy from hooking up with John because they were concerned that he was going to treat her like his other conquests," the source added to website RadarOnline.
"Now, Katy is keeping mum on the subject and won't have anyone tell her, 'we told you so'."