I am in a not dissimilar situation. I am a trainee therapist and my therapist is rather well known in therapy in this country. He too is an author and trainer and involved at a high level. I saw him described as a "big name" in psychotherapy which made me laugh and also made me feel rather proud of him.
One thing I have talked to him about is that in the course of being in therapy with him I have learned more from him than any other teacher by miles. As well as being my therapist he is my teacher and I am lucky to have him as a teacher.
I don't really feel intimidated by him but that might be because I have been his client for a long time and I have seen some of his vulnerabilities and humanness as well as the eminent career stuff.
I want to say your feelings about this are valid. It sounds like it would be a good idea to talk to him about them. If you are feeling something and not sharing it, it could become an obstacle to the relationship but if you bring it into the room it has the opportunity to become part of the work.
You could just say what you said here about having mixed feelngs towards seeing him as a therapist as well as seeing him as a mentor figure and go from there.