1
general::
Also, regular fellow. A nice or agreeable person, as in Luke's a regular guy, or Hilda's a regular fellow. [Colloquial; first half of 1800s]
American Heritage Idioms
2
general::
Phrase(s): a regular guy
a normal and dependable guy. • Don’t worry about Tom. He’s a regular guy. He won’t give you any trouble.
McGrawhill's American Idioms And Phrasal Verbs