The new arrivals join previously announced Sarah Jessica Parker and Pierce Brosnan on the comedy.
Filming is underway in New York and the Weinsteins have earmarked a spring 2012 release.
I Don’t Know How She Does It is based on British journalist and author Allison Pearon’s novel of the same name about a working mother who juggles the demands of a busy job with a hectic family life.
Douglas McGrath is directing and Donna Gigliotti is producing. Scott Ferguson and screenwriter Aline Brosh McKenna serve as executive producers.