TopGunn (born 3 April 1991 in Copenhagen as Oliver Gammelgaard Nielsen) is a Nørrebro-based Danish dancehall / rnb singer and the owner of Cheff Records label. He is also a produced and has produced beats for artists like Kidd, Raske Penge and Klumben.

Topgunn has had influence on the Danish dancehall scene since 2010 when he released his first EP called "Dansehallens Erobrer". At that time he was a part of a soundsystem called FUMA HI-FI. Later he also became a part of a collective called Firehouse, for which he produced dubplates. He became widely known in 2011 when he produced and featured in Kidd's youtube hit "Kysset med Jamel".
He released his debut album "21" in may 2013 via Cheff Records Label. Topgunn released two singles from the album: 'Hemligt Nummer' and 'Tilbud'.

After releasing the album and gaining the popularity in Denmark, he decided not to sign with any major recording labels. He still releases his music independently via Cheff Records. In January 2014 Topgunn released a single "Man kan ikke stole på en lille røv" (English: "girls with small asses are not to be trusted").

His most recent release is an EP called "Mig og mit hoved" (English: "me and my head").

In the beginning of 2011, before launching Cheff Records and recording as Topgunn, he home-recorded and self-published a rap album called '20er i byen' under the alias Shaq Boosie.