Drew Barrymore is begging Jennifer Aniston to dump John Mayer, telling her: "You can do better!" says a friend of the actresses.

The two beauties – recent co-stars in the hit He’s Just Not That Into You – had a recent heart-to-heart talk about the commitment-phobic rocker, pals say, with Drew urging Jen to keep looking because John’s using her to boost his career.

"Drew told Jen she could do way better and she’d be a fool to settle for him," a close pal told The ENQUIRER.

"The first time Jen introduced twice-divorced Drew to John, they clashed," added the source.

"They bickered for so long that Jen had to step in and change the subject."

Over the past 10 months, Drew has heard all of Jen’s horror stories about 31-year-old John’s roving eye, how he blabs about his love life and how he refuses to discuss marriage or children, added the source.

When quizzed recently about what dating advice she gives to girlfriends, Drew revealed: "Don’t coddle your friends, help them grow. Stop repeating those bad patterns. If he doesn’t make you feel good, get out!"

"And even though Jen is crazy in love with John, I think a part of her is worried that Drew may be right."

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