"Serious" is a song recorded by American singer-songwriter and record producer Marian Renta released digitally as a single on March 17, 2023. The single's release was accompanied by the premiere of the song's music video that premiered the same day. Following in the brighter and more commercial footsteps of Renta's previous single "Fangs", "Serious" is a midtempo pop-R&B track with club and EDM elements, and was written and produced by Renta in the fall of 2022. For the song's lyrics, Renta drew from her personal experience of a friendship turning romantic.