master of ceremonies 
noun
A person who presides over a formal event or entertainment and who introduces guests, speakers, or entertainers: the Master of Ceremonies will announce the cake-cutting...
- It is a good idea to have someone acting as master of ceremonies and introducing speakers.
- To add spice to the event, well-known TV personalities were introduced as the masters of ceremonies.
- One story tells of a committee that did this, telling the master of ceremonies to warn speakers that if they went past the allotted time, they would be mowed down with a sharp bang of the gavel.