Jennifer Lopez is inserting herself into the child support battle Alex Rodriguez is having with his ex-wife, Cynthia Rodriguez.

The New York Post reported that the singer attended a Sept. 13 mediation that Alex and Cynthia had.

"J-Lo's presence blindsided Cynthia," the Post said.

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According to multiple reports, Alex currently pays his ex over $100,000 monthly for their daughters Natasha, 13, and Ella, 10. J. Lo is arguing that Alex should only pay $10,000 a month.

"[Jennifer] is driving the bus," a source told the Post.

The report indicates that the behind-closed-doors proceedings are contentious.

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Cynthia recently spoke to the Post about the legal drama, hinting that J.Lo was causing an unwanted wrinkle.

"All I can tell you, there's been a shift, and I'm not sure what to attribute it to," she said last week. "Alex has dated some wonderful women since our divorce, many of whom have had positive relationships with our children. Alex and I have worked well trying to create a stable environment for our daughters and there has never been an issue. Until now."

This isn't a case of Cynthia wanting to get back together with her ex. She's engaged and has a child with her new man.

"Everybody got along," Cynthia said of the relationship between her fiancé and A-Rod early on. "Everything was fine. This is all new."

TMZ said last month that Alex is upset because he feels like he's "bankrolling" Cynthia, her fiancé and the couple's new baby girl.

"Alex always supported the relationship and was appreciative that our children were being exposed to a person of his caliber," Cynthia said. "All was well until recently."

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TMZ reported that A-Rod currently pays $115,000 a month in child support. Cynthia's attorney told the Post that that number is "grossly inaccurate."

A-Rod and Cynthia split in 2008.

"After 10 years of flawlessness, this situation is unsettling," Cynthia said of the TMZ report. "I'm not a celebrity, nor do I care to be one. I lead a conventional life. I'm a mom. I would never try to disparage anyone Alex is dating. It's ridiculous. I try very hard to stay uninvolved. The subject [of Jennifer] is sensitive and better left not commented on in any way."

She is, though, upset that the custody battle has become news.

"That's not the way I was raised, and I find it deplorable that private information is being spread in the news," says Cynthia. "Finances are not an issue for my former husband, and they're not an issue for me. There really is no issue. That's why this is so unsettling."