David Foster and Katharine McPhee Are 'Absolutely Not Dating': Sources

David Foster and Katharine McPhee have had a close relationship since he first met the American Idol alum on the set of the hit reality singing competition when she was a contestant in 2006. But is their relationship more than platonic?

Those watching Foster’s daughter Erin’s teasingly playful Instagram stories Tuesday evening may have gotten that impression — but sources tell PEOPLE viewers missed the point completely.

“This is not at all true,” a source close to the situation tells PEOPLE. “Erin’s quite obviously tongue-in-cheek and sarcastic Instagram comments were pointed at those who can’t seem to grasp that her dad and Kat can be colleagues, collaborators and longtime friends without it being some big romance. They can’t even perform together without people saying they’re headed down the aisle. Erin was messing with people who jump to conclusions.”

A Foster source reiterates, “They are absolutely not dating.”

The three were together on Tuesday night at the Grammy Museum’s third annual gala at The Novo in Los Angeles, where David was being honored with the Architects of Sound Award for his contribution to the music industry.

McPhee, who has previously collaborated with the 67-year-old Grammy-winning producer for a few live performances (including his 2008 PBS tribute concert Hit Man: David Foster & Friends), joined David on stage to debut a track from a stage musical he’s working on.

And Erin couldn’t help but snap them together — sharing photos of two alongside the captions, “Excited about my new step mom,” and “My parents.”

Erin’s caption poked fun at reports her dad had started a romance with the 33-year-old Smash actress. In May, the two were spotted enjoying a PDA-filled dinner date at Nobu in Malibu, E! reported, with an insider telling the publication the two were “very intimate” during the meal.

“David was seen grabbing Katharine’s face and kissing her cheek several times,” the insider said. “Katharine was doing the same to David’s face and they were acting as if they were a couple.”

The pairs were also said to have traveled together (with McPhee’s mom) not soon thereafter on a Vancouver getaway, E! reported.

Reps for McPhee and David did not return PEOPLE’s request for comment.

At Tuesday’s Grammy event, McPhee spoke about how much David means to her.

“He’s an incredible friend and I just pinch myself when I get to spend time with him on a personal level,” the “Lick My Lips” singer told Entertainment Tonight — while wearing a low-cut, asymmetrical black dress. “I love his outlook on life and how he treats people. He’s a really a special person in my life.”

“What I’ve learned from him is how lucky we are to do what we do,” she added. “He’s always reminding me and it’s comforting to know that it’s possible to walk through this life he’s had — working with incredible people, being friends with ex-presidents and world leaders — and still have that perspective. He’s so well-connected, but still just a simple guy from Canada with his little Canadian accent!”

Foster has been married four times before — most recently to Real Housewives of Beverly Hills alum Yolanda Hadid, whom he divorced in 2016 after four years wed and nine years together. He has eight children including Erin and her sister Sara Foster, who star together in the VH1 reality show Barely Famous. (Sara was also at Tuesday’s event, with her husband Tommy Haas.)

McPhee has been married once before, to husband, Nick Cokas. They split in 2013 after six years of marriage. Since then she has been connected to director Michael Morris andher Scorpion costar Elyes Gabel, though she split from the latter in June 2016.