Leonard, 39, had the couple join friends on a group excursion to California’s Joshua Tree National Park, where Pill thought she was in for some serious hiking, he told PEOPLE at Tuesday’s Los Angeles premiere of HBO’s Togetherness, held at the Avalon Hollywood.
Instead, after nearly taking a tumble on the park’s lunar landscape, Pill, 29, said “yes” to a proposal that Leonard had cleared over the holidays with her parents, who live in Canada – and one that their buddies were in on.
“We have astonishingly duplicitous friends,” Leonard said of them keeping the big secret that Pill now calls thrilling.
“It was pretty amazing. I thought we were about to take a picture,” Pill said. When a friend pulled out a camera to capture the moment, “I was like ‘Alright, let’s Wha, what?’ ”
Then Leonard, dropped to one knee to pop the question, later offering a 1920s-style diamond ring recreated by a friend’s jeweler stepfather.
“I told her that I loved her more than anybody on the planet,” Leonard said. “It was pretty good. Her hands were shaking, and so about 30 seconds after I gave it to her I said, ‘You might want to put that on now.’ ”
Pill did eventually wear the ring, posting a photo on Instagram on Saturday of the two together with the caption, “Let’s do this, 2015!!!!”