Cynthia Nixon and Partner Welcome New Son

"Sex and the City" star Cynthia Nixon and her partner Christine Marinoni have welcomed their first child together, according to a report from People magazine.

Education activist Marinoni, 43, gave birth to a boy -- Max Ellington Nixon-Marinoni -- on Monday.

"Christine and baby are doing great," a rep for the couple told the celebrity magazine.

Nixon, 44, began dating Marinoni in 2004 and the pair announced their engagement in 2009.

The actress has two children, Samantha, 14, and Charles, 8, from Nixon's previous relationship with English professor Danny Mozes -- whom she dated from 1988 to 2003.

NewsCore contributed to this report.