In an interview with "The Breakfast Club" on Power 105.1, Lamar, 27, responded to the rumours that he had proposed to high school sweetheart Alford.
"Yeah, definitely. I'm loyal to the soul," he said.
Lamar has managed to keep his personal life private, but the musician opened up about Alford, saying, "She's been here since Day 1."
2015 has already been a big year for Lamar. He won a Grammy for best rap performance in February, and, a month later, released his critically acclaimed third studio album, To Pimp a Butterfly.