The video of the event showed the awed and astonished girlfriend made her way to the stage and the audience erupted into cheers.
On the stage, Weiss proposed with his mother’s wedding ring in honour of her recent death who he said tragically passed only two weeks ago. Svendsen gave a teary but definite yes as her response and the crowd cheered to this.
Glenn Weiss had earlier bagged the trophy for helming the 90th Academy Awards earlier this year.
Svendsen joined him onstage, and he presented her with a ring. "Jan, you're the love of my life, and my mom was right, never let go of your sunshine. You wonder why I don't like to call you my girlfriend? Because I want to call you my wife. I want to put this ring on your finger in front of all of these people and in front of my mom and your parents watching from above. Will you marry me?" he said.
She replied with a "yes".
Later in the ceremony, when "The Americans" star Matthew Rhys claimed the trophy for Lead Actor in a Drama, he quipped that his girlfriend and fellow nominee Keri Russell said, "'If you propose to me, I will punch you clean in the mouth.'"