Green’s Dictionary of Slang

two eyes of blue! excl.

[rhy. sl.]

too true!

1972		Dodson & Saczek Dict. of Cockney Rhy. Sl.
1984		Partridge DSUE (8th edn) 1280: [...] since ca. 1925.
2002		B. Kirkpatrick Wicked Cockney Rhy. Sl.