Charles Leclerc has promised he will "work harder than ever" to justify Ferrari's faith in him - but not before he tries to sign off in style with Sauber.

Leclerc will leave his current employers to join Ferrari in 2019 as a replacement for Kimi Raikkonen, who will move in the other direction on a two-year deal.

The 20-year-old - who won the Formula Two championship last year - will partner Sebastian Vettel after impressing in his debut Formula One season.

A Ferrari driver academy graduate, Leclerc posted a series of messages on Twitter to reveal his delight at the move while also thanking those who helped him get the opportunity, including his late father.

"Dreams do come true... I'll be driving for Ferrari for the 2019 Formula 1 world championship," he wrote, adding a picture of his next team's famous badge. "I will be eternally grateful to Ferrari for the opportunity given. To [manager] Nicolas Todt for supporting me since 2011.

"To my family. To a person that is not part of this world anymore but to whom I owe everything of what is happening to me, Papa. To Jules [Bianchi], thank you for all the things you [taught] me, we will never forget you, and to all the persons that supported me and believed in me.

"I will work harder than ever to not disappoint you. But first, there is a season to finish with an amazing team that gave me the opportunity to fight and show my potential. Let's go Sauber."

Ferrari confirmed Leclerc's impending arrival just minutes after announcing Raikkonen will depart at the end of the current campaign.

The Finn is in his second spell with the Italian team - he won the 2007 world title with them in his initial stint but has not registered a race win since returning in 2014.