To say that there is no ego in a person who does public speaking regularly or for a living would be clearly a false statement. But for those of us who only speak from time to time, when you see a speaker who can walk out in a room of 30 people or a auditorium of 3000 and literally "own the room", it really is an amazing transformation. To imagine how you could ever be that much larger than life is mind boggling.
But in a lot of ways, when you step out to talk to a group of people, you do become larger than life. That is because you are doing the impossible. You are having a conversation with dozens of people all at once. Now, whether you feel like you are having that conversation or not isn't important. If your talk is not interactive, you may not know the dialog is happening. But in the minds of every single individual in that hall, they are interacting with you. What you are saying is getting down inside of them and they are reacting to it. But even more than what you are saying, how you are saying it is having an even bigger impact.
So are there things you can do to "become" larger than life? Well there are some ways of behaving in front of a crowd that differ from daily life. We do have to accept that you will develop a "stage persona" that is different from your daily personality when you speak to a group. Does that make you a phony? No. Both of those personalities are you. It is just a different you when you relate to a group than to people one on one and it seems strange because that form of you only comes out on stage. But it isn't a Dr. Jekyll, Mr. Hyde thing. Just as you speak to a child differently than you speak to an adult, you will develop a way to talking to a group that differs from speaking to an individual.
Part of becoming larger than life is learning to what they call "own the room". This sound egotistic and strange but it really does work when you are about to speak. Owning the room simply means that when you step out in front of that crowd, they are no longer some random group of people, they are YOUR people. They are there to listen to you and what you say is of value to them. If you had any ego problems before you stepped out in front of that audience, check that ego problem at the door.
You must assume that you are adored when you speak to a group of people. This doesn mean you strut about like God's gift to the world. But it does mean that you recognize that your value to this group is as a speaker and that your services are wanted and needed here. In fact, the only way you will be an effective public speaker is if you own the room. Treat that room like it was your home and these people came here just because being with you is just that great. If you step out there with that attitude, the audience will buy into your attitude and they will give you the room and be glad you took it over.
It can be a bit strange if you watch yourself become larger than life. But you can be humble about it and just recognize it is part of the craft of becoming a great public speaker. And if being good at this art you are gifted to give to the world means owning rooms and becoming bigger for an hour or so, well then why deny the world that experience? Enjoy it and let others enjoy it too.