go back a long way
To have known someone for a very long time. Oh, Caitlin and I go back a long way—we've been friends since kindergarten, in fact!
go back a long way
mainly BRITISH or go way back
mainly AMERICANIf two or more people go back a long way, they have been friends for a very long time. We go back a long way, and she's always kept in touch, always been there for me. This here is Dan Parker. We go way back.
go back a long ˈway
(of two or more people) have known each other for a long time: John and I go back a long way, don’t we?