Katharine McPhee showed off her husband David Foster's cheeky response to a flirty message she sent him on her Instagram Story Tuesday.

The 37-year-old musician had sent Foster, 71, a video of herself posing in blue lingerie on a bed. 

"I'm an underwear model now," McPhee wrote in the text message exchange.

"Vava VavA-voom Hot mom —  I tried u a bit ago but u are obviously busy stripping [crying laughter emoji]. U look amazing!!! Wow!!!" Foster responded.

KATHARINE MCPHEE, DAVID FOSTER SMOOCH ON DINNER DATE AFTER WELCOMING SON

David Foster and Katharine McPhee got married in 2019 during a London ceremony. The couple shares one son. (Photo by Frazer Harrison/Getty Images)

McPhee and Foster got engaged in 2018 after dating for less than a year. The couple tied the knot in a London ceremony in 2019 and welcomed their son Rennie earlier this year.

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The "Over It" singer previously revealed that she was hesitant to enter into a relationship with Foster due to the couple's age gap during an appearance on "Dr. Berlin's Informed Pregnancy Podcast."

"It took me awhile to kind of come around to really want to have a real serious relationship because I was very concerned with what people would think, and also I just wasn't there yet either, too," she said.

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"I had been single for the last year so I was still in kind of that world, and I've known him for so long, and I knew he really liked me. It took me awhile."

Foster has five adult children from previous relationships. McPhee and Foster first met in 2006 when McPhee was a contestant on the fifth season of "American Idol" and Foster was a mentor on the singing competition series.

McPhee is the Grammy winner's fifth wife. 

Fox News' Jessica Napoli contributed to this report