"Well, the last time I saw my natural hair color, I was probably about 12 years old, but I thought it might be time to give it a second chance," Underwood wrote in her caption bef

Underwood will debut her darker hair on stage as she performs the opening for Sunday Night Football as the Cowboys take on the Eagles on September 4, marking her 13th season. "We’ll be waiting all day to hear it once again!" the network shared in a nod to Underwood's hit song.