the term Oh my lady gaga is a popular chinese expression used instead of oh my God. the Cosmopolitan magazine is calling it the expression of the moment (end of 2010)
Derived from Red Dwarf, it is used when Rimmer attempts to simulate Jacobean courting. It means a man who uses a cheesy move to try and pull a woman. It's very similar to "Oh Matron!" from the Carry On films.
Katie just said that I had a lovely smile. She's hotter than the sun! I'll try yawning and putting my arm around her slender shoulders. Oh my lady!