Rosie O'Donnell -- Wife Doesn't Really Want Custody ... She Wants Money

1:40 PM PST -- Round's attorney William London tells TMZ that his client is only seeking full custody in the best interest of their daughter, it has nothing to do with money.

Rosie O'Donnell is fighting back against her estranged wife, and sources connected with Rosie say the wife is going for full custody of their daughter for one reason ... money.

Michelle Rounds is filing legal docs Tuesday, asking for full custody of their 2-year-old daughter Dakota. Michelle's lawyer told the New York Post full custody is necessary to protect the child's "general welfare."

But our Rosie sources are scoffing, saying that the couple has a prenup and this is nothing more than a money play, adding Rosie is a "devoted mother" and her parenting skills and dedication are well-documented.

The sources say Michelle is trying to hit Rosie where it hurts the most so she'll open her wallet.