But in an interview likely conducted weeks or more ago for the cover of Health, she insisted that she's "pretty single."
"I had a relationship with my lead actor on my show [Elyes Gabel on Scorpion] that was almost two years. I still am crazy about him, and we have a really great working relationship. It’s definitely not the easiest thing to get over someone you see every day! It’s still an adjustment. But I haven’t had anything super serious since."
Her character and Elyes' character are together on Scorpion, so they still kiss.
"Kissing each other feels very natural," she admitted. "Sometimes I’ll slip him the tongue, just to be rude."
"We're very close friends. I’m really, really fond of him, and I think he’s an incredible person," she said of David. "I’ve known him since I was 21 years old, you know? He produced my first single. So he’s been really good to me. People can say whatever they want."
David's own daughter Erin captioned a photo of McPhee on an Instagram story with "Excited about my new stepmom," but Katharine says that was a joke.
"So we were sitting there at the table, and she said, 'Do you wanna, like, do a thing?' And I was like, 'OK.' So I mean, we were in on it. She’s so funny — I mean, you saw what she wrote about 'my parents.' Truly, you think that’s how she’d announce it? On Instagram?"
She also told Health what she's looking for in a potential partner.
"Someone’s who’s spontaneous and adventurous, who’s ready to just go do something — or let you go do it at the drop of a hat. I’m so independent now; I wasn’t really that independent when I was in my 20s, so I need to be with someone who has their own life."
David was married to Yolanda Hadid from The Real Housewives of Beverly Hills until announcing their divorce in December 2015, while Katharine divorced Nick Cokas in 2016 after eight years of marriage.
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