Songfacts®:

• Milton Keynes-based rapper Tom Austin started making music at the age of 18. His first track, "Mary Berry," became a huge viral hit in the UK in 2019. For his rap moniker Austin took the name of Grand Theft Auto IV's eastern European gangster character Niko Bellic, shortening it to Niko B.
• The song details the everyday goings-on of Austin's teenage life. He recounts tales of dancing in the street at 2 a.m. and getting rid of his irritating girlfriend by planting coke in her purse and calling the police. The chorus finds him eating a Big Mac and removing the gherkin. Bellic said his hope for the song is that listeners will immerse themselves in his world:
  
  "I always wanted an artist I could relate too. I just want people to hear Who's That What's That and dance while not taking anything too seriously. I want teenagers to understand they can do anything they want and create anything from just being in their bedroom."
• Niko B originally wrote the song in 2019 but kept delaying the release. He told BBC he felt Christmas wasn't a good time, then when it got to February 2020, he thought he'd "wait until the start of summer as it will be a good summery song."
  
  Then lockdown hit, so Niko B dropped the track on May 21, 2020, knowing "a lot of people were in the house and focusing on their phones."