...Katharine McPhee KISSING 'SMASH' DIRECTOR Both Married to Other People...

Katharine McPhee is dating her former "Smash" director Michael Morris, .. and they're even making out in public -- problem is, THEY'RE BOTH MARRIED TO OTHER PEOPLE. 
Morris is married to actress Mary McCormack (who played Howard Stern's wife in "Private Parts") ... and they have 3 young daughters together, ages 2, 6 and 9.

29-year-old Katharine is married to 47-year-old producer Nick Cokas -- they have no children.
Sources close to Katharine and Nick tell us... the two have been separated for 6 months and are living apart. They were married in 2008.