Google CEO Sundar Pichai announced six new voices were coming to Google Assistant today. In addition to these voices, John Legend has worked with Google to train their machine learning Wavenet algorithm to convert his voice into another Assistant voice that will be coming out later this year. Once available, you will be able to hear Legend telling you the weather, your upcoming schedule, and answers to your questions. To see this in action, you can view the video below. You can also hear Legend singing, answering questions, singing, and speaking brief sentences.
Source: https://www.bleepingcomputer.com/news/google/john-legend-and-6-other-voices-being-added-to-google-assistant/