Katharine McPhee -- Touched ... by Estranged Hubby Nick Cokas

Katharine McPhee's estranged husband gave her a hand Tuesday ... a very gentle hand.

It's a stark contrast to her split with Nick Cokas, which allegedly came after Katharine was photographed sucking face with her "Smash" director Michael Morris. Katharine claimed in the documents she was already separated from Nick, but he says they were still together.

But things change ... or do they? A source close to Katharine insists Katharine and Nick had a friendly business breakfast in West Hollywood. He's still involved in her music stuff.