In a new lawsuit filed against Carrie Underwood, her producer, the NFL and more parties, a struggling songwriter named Heidi Merrill claims Underwood's theme song for Sunday Night Football was lifted from a song she submitted to Underwood's producer, Mark Bright.

The Blast obtained court documents in which Merrill claims that her song "Game On" provided the basis for Underwood's song of the same name, which has served as the theme song for Sunday Night Football since Underwood first recorded it in 2018.

Merril's filing claims that she and three other writers co-wrote "Game On" in 2016. She uploaded it to YouTube in March of 2017, where it has since received just over 1500 views. The recording was also featured during a broadcast of CBS Inside College Basketball.

The songwriter says she attended a conference in Nashville in August of 2017 mainly because she knew Bright was scheduled to attend, and she claims she knew Underwood was looking for a new theme song for the upcoming 2018 season of Sunday Night Football. She alleges she spoke to Bright about her song, and he asked her to submit it via email to his assistant. Two months later, she claims, she received an email passing on the song.

Underwood subsequently debuted a new theme song titled "Game On" when Sunday Night Football returned on Sept. 6, 2018. The superstar co-wrote the song with Chris DeStefano and Brett James. Merrill claims the track is "substantially — even strikingly — similar, if not identical" to her original work. Check out Underwood's song below.

Merrill's lawsuit names Underwood, Bright, NBC, the NFL and more parties, alleging copyright infringement. The filing seeks damages in an unspecified amount. Neither representatives for Underwood nor the NFL commented when contacted by the Blast.

Merrill previously had some limited success with a song titled "Cornhusker Strong" in 2015. In an interview with local NBC affiliate KSNB in Hastings, Neb., Merrill said the song was inspired by her Nebraska roots. Her video of the song has nearly 275,000 views on YouTube, and it's been shared by sports outlets including 247Sports.com, Scout.com and Huskerspot.com.

In her filing, Merrill claims "Game On" was intended as a way to capitalize on more sports-themed material. She also cited a previous lawsuit filed against Underwood and Bright over Underwood's No. 1 hit "Something in the Water." That suit was later dismissed, according to the Blast.

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