This is Iris Kessler, a 16-year-old from Pickerington, Ohio.
She has an 18-year-old brother called Grant and two older sisters called Bronwen and Olivia, 20 and 23. Her family got bigger recently, after Olivia gave birth to a baby girl, Carter.
While Iris waited with her family at the hospital in Columbus to meet Carter, her brother Grant turned up in clothes he thought were fitting for the occasion – a suit and tie. He even wore a tie clip.
People really appreciated the effort Grant put in before meeting his niece, and Iris's tweet has been retweeted more than 30,000 times.
Iris said seeing the tweet blow up was "insane", and that Grant was trying to stay cool about it. "But I can tell he's kind of freaking out inside," she said. "It's pretty adorable."
Iris told BuzzFeed News this was "totally classic" behaviour from her brother. "He's always the type to show up to things dressed up, or bring a cake for no reason," she said.
While Carter may not remember meeting her dapper uncle, Iris said "she's going to grow up hearing this story so I'm sure she will know that it happened, and think it's funny".
Carter did, however, seem impressed when she finally got to meet her uncle. Maybe.
Iris's mum and Carter's grandma, Karen Kessler, told BuzzFeed News Grant was "extraordinarily excited, proud and protective regarding the birth of his first niece. His dressing up was both a show of respect and a way to honour her arrival."
She added that her children "all have incredible gifts like this. Iris's is knowing what resonates with people."