She probably knows that. LOL but technically the song had to have been out on Radio before MTV launched and made it their first video.
She told Collider: "I'm very excited about Thor 2. It's great. [Sif] definitely has a lot more action and does some great scenes where she gets to fight side by side with Thor.
"You really get to see how much love she has for her fellow Asgardians because she puts her life on the line and risks a lot to save a few Asgardians."