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LaBelle invited Gaga to join her on stage -- teal wig, boob pasties, studded thong and all -- at the star-studded after-party at the Standard Hotel. The unlikely duo belted it out, complete with diva-esque hand waving, with their arms wrapped around each other and sharing one mic between the two of them.
Earlier in the night, Gaga won the prestigious prize for Fashion Icon at the Council of Fashion Designers of America award ceremony, after suffering a very revealing wardrobe malfunction on the red carpet and mistakenly calling iconic fashion editor Anna Wintour the "B" word.
After the duet that brought the house (club) down, Gaga proceeded to rage -- dancing and singing the night away.
Watch Lady Gaga and Patti LaBelle perform and Gaga party.