Cartwright who has voiced the popular character for more than three decades, confirmed this in a new video posted to TikTok.
The actress captioned the video: "The rumours are true! Sabrina Carpenter is my niece!".
Responding to a question from a fan on the site as a picture of her and Carpenter flashed up on the screen, Nancy Cartwright said: "Yeah, absolutely".
She also added: "Isn't it amazing to find out that somebody you have known for a little while, doing this little 10-year old-boy for 35 years, I'm related to this, like, superstar".
At the end of the video, Cartwright praised her niece Sabrina, saying: "She's pretty amazing".
Before bursting onto the scene as a popstar, Sabrina Carpenter found fame after starring in Disney Channel's Girl Meets World. Carpenter's new album 'Short n'Sweet' is to arrive on August 23.
The singer is currently dating Irish actor and Saltburn star Barry Keoghan, and is a close friend of US singer Taylor Swift.
