The musician attended a party to celebrate the start of the NBC series and uploaded a photograph of herself with Kinney and his co-star Jesse Spencer to Twitter.
GaGa, who has reportedly been dating Kinney for over a year, had earlier urged her followers to tune into the firefighting drama.
"My bf Taylor is on TV TONIGHT!!! for the premiere of CHICAGO FIRE on NBC at 10/9c in America," she wrote. "Monsters, wanna watch it with me+chat online?"
She posted several pictures of the premiere party, saying that everyone was "so happy", and also retweeted fans who had tuned into the show.
Meanwhile, when a fan suggested that she should be a guest star on the series, she replied: "only if Taylor rescues me!"
When the show was over, she added: "Time for bed. Thanks for watching. The cast works so hard and are great friends.x"
Kinney recently revealed that he is "happy" in his relationship with GaGa, saying: "Everything is great!"
Chicago Fire, which also stars Monica Raymund and Lauren German, focuses on the firefighters, paramedics and rescue squad working in Chicago Firehouse 51. The show airs on Wednesdays on NBC.
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