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Katy Perry paid a visit to a sick fan in Australia after she had to miss the star's concert on Monday.
Eight-year-old Grace Moores had brain surgery last week after being told she had a 6cm tumour.
Her sister Tiana, 16, tweeted that Grace had been looking forward to the concert before she was diagnosed in April.
Katy's team got in touch with Tiana and went round on Tuesday before her concert in Adelaide that night.
Tiana tweeted that Grace has been "Katy's biggest fan since she was three".
She started the hashtag #HelpGraceMeetKatyPerry to try to catch the attention of the American singer online.
Her original tweet had more than 20,000 retweets.
And then, on Monday, Katy's people got in touch.
Tiana announced: "We did it."
Tiana shared clips on Snapchat of Katy hanging out with the family.
The 33-year-old, who recently said she suffered "bouts of situational depression" following her last album, performed songs including Roar and Chained to the Rhythm.
And she also took one of the greatest snaps of all time.
Katy shared a clip of her with the family to her 71 million Instagram followers.
She called Grace her "new merch model" and showed the eight-year-old with a signed Katy Perry shirt.
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