The network said Barry has signed on as news anchor, while Perlina Lau will be the show's social media presenter.
"Hilary is one of the most talented broadcasters in the country and it is time to see and hear more of her," Head of News Mark Jennings said.
"She is a world-class newsreader, but she is also an astute observer of life and what makes New Zealand tick ... Hilary's personality and wry sense of humour makes her the perfect foil for Paul."
Barry will remain as 3News' co-host. Lau, who wrote and starred in popular web series Flat3, has been a director's assistant at 3News for two years.
The Paul Henry Show is scheduled to air simultaneously on TV3 and RadioLive.
It is rumoured to be kicking off in May once the show's custom-built studio is finished, and will air from 6-9am.
- nzherald.co.nz
