The 32-year-old singer has documented her efforts to track the Canadian star during her stay in the French capital, posting a video of Celine posing for a photoshoot on a balcony on her Instagram story.
As she sees Celine from a distance, Kerry says: ''There she is. Celine Dion in Paris. On a balcony.''
And as Celine puts one leg on the balcony as part of the photoshoot, Katy shouts: ''Yes queen! Oh, work that leg. Work that leg. Yes queen. Yes!''
Katy is a long-time fan of the music icon and hailed Celine following her memorable performance at the Billboard Music Awards in May.
Celine, 49, sang her chart-topping single 'My Heart Will Go On' at the annual awards bash in Las Vegas.
And Katy wrote on Twitter: ''OMG @celinedion I HAVe always lived for you PLS BEAT YOUR CHEST AT THE END OF THIS PERFORMANXE #BBMAs (sic)''
Meanwhile, Katy recently claimed One Direction singer Niall Horan wants to date her.
But, the 'Bon Appetite' star said: ''I see him around all the time, he's always trying to like get my number to like maybe flirt with me but I'm like 'I could babysit you I'm like your mum!'''
By contrast, Niall has insisted there's nothing going on between the pair.
Niall explained: ''I don't know if it's in the accent or the way we put things but I guess that stigma of Irish charm follows you around a bit, which is not a bad thing really.
''I don't know what [Katy's] talking about, by the way. I texted a mutual friend who works on her team saying, 'I heard you guys are going to be down in Australia'. Katy has taken that and run with it and embarrassed me in front of the whole world.''
Sometimes actors are not acting.
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