Guilherme Kaue Castanheira Alves (born 19 May 1998), known professionally as MC Gui, is a Brazilian funk ostentação singer, songwriter[1][2][3] and racing driver.

At the age of ten, he, together with his brother, had fun creating funk lyrics, and that was when his father decided to invest in an artistic career for Gui.

[4] In February 2017, Gui was confirmed as one of the participants in the talent show Dancing Brasil, shown by RecordTV.

[9][10] On 21 April 2014, Gui lost his brother, Gustavo Matheus Castanheira, initially suspected of having a cardiac arrest.

A black Land Rover Discovery, which was the singer's car, was unlicensed and also had a lot of traffic fines.

In November 2018, Gui's father's production company had documents and drugs seized by the Civil Police.

[22] On 14 March 2021, during a critical period of the COVID-19 pandemic, Gui was detained by the Civil Police in a clandestine casino in the city of São Paulo.