Frei has been handed the role of Washington Correspondent and will also join the main presenting team, hosting shows such as Dispatches. Newman will join Jon Snow and Krishnan Guru Murthy as the third regular presenter after five years working with the broadcaster.
Newsnight's Jackie Long will be the new Social Affairs Editor. A Science Editor is currently being recruited to complete the new lineup.
Chief creative officer at Channel 4 Jay Hunt said: "These new appointments to Channel 4 News will simply reinforce its reputation for agenda-setting journalism. Matt Frei is a truly exceptional correspondent and writer and Cathy's political insight makes her the perfect addition to the presenting team."
Jim Gray, editor of Channel 4 News, added: "We're thrilled to welcome these new journalist heavyweights - the perfect mix of home grown talent and established names. Matt joins us with an impressive track record at a time when the world's news and the US view on it needs explaining like never before.
"Cathy has quickly established herself as a journalistic force to be reckoned with - she will have a chance to bring those skills to bear in the studio.
"And Jackie's connection to modern Britain through her reporting in this area will be a great asset to us. It's an exciting time for the programme."
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