The 29-year-old actress and Livingston began dating in 2012, reported Us magazine.
The former child star was mostly tight-lipped on the details of her romance with Livingston, but they did work on the same show.
She and Livingston, 28, have guest-starred as Olivia Lyon and Chicken, respectively, on the FOX hit "Empire".
Livingston also appeared as a contestant on "America's Next Top Model: British Invasion" in 2012.