She is beautiful and a fantastic singer! 
I can’t speak for the video, but Lucy Thomas is a real person.
I had never heard of her before I Googled this song:
Aye lad, she’s from oop North (Wigan): slight_smile:
There have been cases lately of an overly-made-up woman (with perfectly symmetrical features) being accused of being an AI invention.
Even spectators at World Cup matches… sheesh…
The video goes for nearly a minute before the first cut, without her lips going out of synch with the music or her hair turning into a bird or growing an extra arm or anything. I don’t think any of the current AI video generators are capable of that.
And her singing is a little too breathy for my tastes, but don’t let that stop you.
Okay, I’m convinced she’s real, and she can serenade me any time she wants! 
The gold standard for such decisions.
Nope. Just a sparse presentation. Only the singer, no background, performing like she might on a stage. And seemingly “lip synching” with a previous in-studio recording, as is fairly standard in music videos.
(I put lip synching in quotes because she’s likely really singing. Just we likely aren’t hearing the actual audio from this performance. That could create a slight disparity your subconscious notices.)
Easiest way to check on YouTube is to just look at their account page. She has videos going back eleven years so, unless she decided “Screw it, going to AI myself” she’s probably legitimate. Also if they have upcoming live performances.
It’s possible that someone can be brand new, unready/unwilling to perform live, etc so absence of these things isn’t an absolute indicator that it’s AI but, if they have a history going back years, you’re almost certainly dealing with a real person.
In the opposite direction, a new artist with a ton of uploads in a short period is a good candidate for being AI. I once came across a YT song that sounded catchy, looked at the account and they had about a hundred full videos uploaded that month. I assume their channel moderation was botted as well (or maybe just some foreign worker) since I snarkily asked “Hey, is this AI? You have twenty videos this week!” and got a heart/liked response to my posting.