A rep for Stefani confirmed to ABC News that the two singers are dating each other.
According to People magazine, the relationship is relatively new, though the "Voice" co-stars have already begun traveling together. The magazine reported that Stefani is currently in Nashville with Shelton, who is set to attend the CMA Awards tonight.
"They've been supporting each other through a difficult time and they're really happy together," a source told the magazine. "Everyone is thrilled because they're both incredibly nice people."
This past July, Shelton, 39, and his wife of four years, fellow country star Miranda Lambert, announced they were divorcing. In August, Stefani, 46, and her husband of 13 years, singer Gavin Rossdale, announced the end of their marriage.
Lambert is also expected at the CMA Awards.