The 22-year-old was one of Tottenham's players of the season in an excellent 2015-16 campaign which saw Mauricio Pochettino experiment by using him in a defensive midfield role - and it paid off.
The former Sporting Lisbon man has been used there by Roy Hodgson in both of England's games in Euro 2016 so far - a 1-1 draw with a Russia and a 2-1 win over Wales - and looks set to start against Slovakia tonight.
Obviously, it is Dier's first major tournament with England, but Keown says it looks like the Spurs machine has been competing at this level for years.
However, the ex Arsenal man says that Dier - who scored a wonderful free kick in the opener against Russia - is not as adventurous with his passing as he ought to be.
"Dier has slotted into the side as if he’s been playing for England for years and, given his two fine displays already, he is more than capable of dealing with Hamsik’s threat," he told The Mail.
"What I’d like to see now is for Dier to start making more forward passes."
If England do go on to win the competition then Tottenham will played a big role in that, with Dier one of five Lilywhites figures in the first XI from the first two games, with Kyle Walker, Danny Rose, Dele Alli and Harry Kane also involved.