Bias caused by the opinion of a famous person on matters they are not well-educated on? What is the name of the bias caused by the fame of a person on subject matters they are not experts on?

E.g: If a celebrity they like talks about climate change, people might tend to read, discuss, and follow their views as opposed to that of an educated climate scientist.
I don't believe that there is a cognitive bias that has been accepted by the scientific community that fits your fact pattern.  You can look for a matching cognitive bias yourself in this list:

https://en.wikipedia.org/wiki/Overconfidence_effect#Better-than-average_effects

I don't see one.  In fact, I don't even think people would believe a celebrity over an educated climate scientist on the current status of climate change.  It may help the person remember the ad or public announcement because a celebrity was the one to announce it but I doubt the credibility of the celebrity exceeds that of the scientist.