Jennifer Aniston's efforts to keep her man may have been in vain following reports that John Mayer tried to pick up another woman while on the European leg of his tour.

California native Chaton Anderson claims that the singer came on to her in a Dutch coffeeshop on June 20.

“I think he thought I was from Amsterdam, because he said, ‘I am John and I am a singer,’ she tells In Touch.

“I laughed because I knew who he was.”  

Anderson says Mayer did his best to to convince her to have dinner — or after-dinner drinks — with him.

“I asked him what his relationship status was,” she says. “He said, ‘It’s vague.’ I asked him what that meant and he said, ‘You know, it’s very vague.’

"I just laughed. I never mentioned Jennifer and neither did he.”  

Chaton says she gave Mayer her cell phone number but the phone was later stolen.

“I’ll never know if he called or not,” she says, adding, “I never would have guessed he had a girlfriend at all.”