Is Cameron Diaz getting ready to be a stepmom to Alex Rodriguez's two daughters?

The actress, 38, sure looked like she was over the weekend in Mexico, where she and the Yankees slugger, 35, kicked back with his little girls Natasha, 6, and Ella, 2.

PHOTOS: Would Cameron and Alex have dated in high school?

Diaz appeared at ease holding little Natasha, Rodriguez's eldest with ex-wife Cynthia, whom he divorced in 2008 after six years of marriage.

The on-and-off couple rekindled their romance in November after taking about a month off, and a source close to the pair told Us "they break up and get back together all the time."

PHOTOS: Cameron's past loves

Whether or not she's getting closer to Rodriguez's girls, the Green Hornet actress might not be the marrying kind.

PHOTOS: I'm dating an athlete!

She sniped to UK's Stylist magazine in July: "I think the big misconception in our society is that we're supposed to meet the one when we're 18 and we're supposed to get married to them and love them for the rest of our lives. Bulls**t."

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