The 'Girl Of Fire' hitmaker is set to join the 'Get Lucky' hitmaker on the hit reality show later this year as he tries to coach his team of aspiring musicians into the final of the singing competition.
Keys, 33, revealed the news on her Twitter account.
"My friend Pharrell invited me to be a mentor for his team on 'The Voice'! His team killed it," she tweeted.
Willaims, who joined the panel of the show this year along with Gwen Stefani and original coaches Blake Shelton and Adam Levine, replied, "Can't wait Alicia Keys."
Meanwhile, the upcoming seventh season of 'The Voice' will also feature coaching from Fleetwood Mac songwriter, Stevie Nicks on Adam Levine's team, while Blake Shelton has called in country group Little Big Town and Gwen Stefani has called in her rocker husband Gavin Rossdale to help mentor her chosen musicians.