Kirkland trained alongside Pickford at Preston North End in 2015, and the 36-year-old has claimed that England's most expensive goalkeeper is 'the best he has seen'.
"He is something special," Kirkland told Sky Sports News. "I told Liverpool to sign him 18 months ago. You could have got him for a lot less then.
"He's the best I have worked with. He's a very confident lad and he doesn't have a weakness in his game. Normally with goalkeepers sometimes they are struggling with one aspect of the game but this lad has got the lot.
"His distribution is second to none, he makes the saves which 'keepers should make and his command of his box is the best I have ever seen."
Pickford is currently with England Under-21s at the Under-21 European Championships in Poland.