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The pair were inside a limousine en route to promote the latest series of their show Joan & Melissa: Joan Knows Best? on Good Morning America when the incident occurred.
It is believed that when the car pulled away from Rivers's Manhattan apartment, a manhole cover blew up and rose into the air.
Joan Rivers joked to the New York Post: "We could have had our premiere and the finale on the same day."
Joan & Melissa: Joan Knows Best? premieres tonight on WE at 9/8c.
> Joan Rivers supports Giuliana Rancic: 'We want her back on E!'
Watch Joan and Melissa Rivers talking about their new season on Good Morning America below:
