Katharine McPhee -- Getting Snuggly at Work ... Again

Katharine McPhee can't keep her hands off her co-workers ... but it's not a director this time ... it's her new show's leading man.

McPhee was on set Thursday getting handsy with Elyes Gabel, her co-star in the upcoming CBS series, "Scorpion." Unlike her last on-set romance ... Gabel's not married and she's getting divorced.

You'll remember ... photos surfaced of McPhee locking lips with "Smash" director Michael Morris in October 2013. McPhee was married to Nick Cokas (though she claims they were separated) and Morris was married to actress Mary McCormack (they're still together).

Her next project will be interesting ... what the hell will she do if she co-stars with Neil Patrick Harris?