Rex Laurent (formerly known as OSKAR O.) is the musical project of singer, songwriter, and producer Olivia Rittenburg.

She began releasing music under the OSKAR O. moniker in late 2018, putting out three projects. In 2023, she reintroduced herself as Rex Laurent. Her debut EP under this alias, Religious Psychosis, was first released under her previous alias, and later moved to this one.

Her debut full-length album as Rex Laurent, Seller’s Remorse, dropped July 18th, 2025, supported by seven singles. She released a subsequent deluxe edition, titled Seller’s Remorse (the afters), October 9th, 2025, featuring four more tracks.