The pair donned hot pink Yes We Plan birth control T-shirts in a new clip to show their support for Planned Parenthood, an organisation which provides sexual and reproductive health services to women in America and is backed by Obama.
A statement from The Kids Are All Right star Moore reads, "Millions of women rely on Planned Parenthood for their basic healthcare and it is up to us - to every woman across the country - to support the only presidential candidate who gets this."
And No More Drama hitmaker Blige echoed the same sentiment, adding, "When I was a teenager, I don't know where we would have gone if Planned Parenthood wasn't there. Not just for me, for my mother, my sisters, my friends. They're about preventive care. As a woman - even as a teenager - where would we be if Planned Parenthood wasn't there for us?"
Actresses Elizabeth Banks and Maggie Gyllenhaal have also voiced their support for the programme in similar ads and opinion columns.
Obama's chief rival, Republican Mitt Romney, is against the Planned Parenthood message.