That's precisely what they did with Doodle God to imitate Morgan Freeman [0] and how James Veich deep faked David Attenborough in his PLnaT eRth video [1].

[0]: https://www.mercurynews.com/2021/07/20/how-the-doodle-god-un...

[1]: https://youtu.be/-CopbQ_QgmM?si=gkbWEva_qqG8dTib&t=205