She is the daughter of English musician Jon Anderson, of the Prog Rock band, Yes.
Have not watched the film, but wary of yet another non-Native production featuring people we don't know, promoted by non-Natives throwing around titles like "Chief". Julian means well, but he didn't sound like he was joking. In his posts he sounded like he believed she'd been given special access and was some kind of cultural mediator or "interpreter".... which never goes well.
Looking at the Facebook page for the movie, it looks like it's non-Natives who like it. None of our Native friends have liked the page. Some Lakota friends have criticisms of some of the people involved in the film, but we're still looking into that, and waiting for more info on what they think of the production as a whole. No L/D/N people any of us know are promoting it.