"Totally dark, only stars", she said, jokingly adding that he "thankfully" didn't push her off the cliff.
Foster and McPhee have been linked since previous year, when they were spotted on a dinner date in Malibu. "I mean, listen, we approve of whoever is going to be good to my dad at the end of the day and we're very honest about it".
The couple is now enjoying a vacation in Europe together, and a source tells E! The Canadian music mogul popped the big question while the couple enjoyed a European vacation on the island of Capri on Sunday. Foster's daughter Erin told People in October, "She's fantastic". Katharine was previously married to the also much older Nick Cokas from 2008 to 2016.
Foster has been married four times and has five children.
His actress daughter, Sara Foster, has also has been open about her father's relationship with McPhee, dropping hints about their romance before the couple officially acknowledged the dating rumours.