Milner has established himself as one of Klopp's key men at Anfield, and the Englishman starred as Liverpool beat Paris Saint-Germain in the Champions League on Tuesday night.
However, Klopp has suggested that the form of the 32-year-old should not come as a surprise given Milner's performances in the same competition last season.
At a press conference, Klopp told reporters: "It's not just this season, last year he had most assists in Champions League.
"Only in football it sounds like 32 was a massive age. In all other parts of life you are still young, and he is still young. He is a top professional and his body gives him a chance to do so.
"James is the best example for them. He is a very energetic boy and likes to cover big distances. He can play football, and that makes him a pretty valuable player."
Milner is likely to feature when Liverpool host Southampton in the Premier League on Saturday afternoon.