England coach Eddie Jones has backed Billy Vunipola to become the best number eight in the world rugby.
Jones' comments come after Vunipola produced an inspiring display to lead England to a 15-9 win over Scotland in their Six Nations opener last week.
Vunipola has impressed Jones since the Australian replaced Stuart Lancaster after last year's failed Rugby World Cup campaign, among the side's three vice-captains alongside Mike Brown and Owen Farrell.
And Jones believes the 23-year-old is destined for the top.
"I tell Billy every day how good he can be. Every player needs to have a dream. As a coach one of your jobs is to give them dreams," Jones said.
"I don't want him to be the best number eight in the Premiership, I want him to be the best number eight in the world. And he can do that."
As for the player himself, Vunipola is loving life under Jones.
"I respond more to the love and compassion he [Jones] shows the boys, me especially," the Saracens star added.
"He is very personable. He has been really good for me since he came in.
"He has just filled me with confidence and that is something I thrive on. I don't need someone to shout at me. I know what I have to do. I just need someone to reassure me and look after me."