Taylor Swift is Diet Coke's new golden girl!

The 23-year-old country songstress released the above video ... announcing to the world that she has partnered up with the soda giant.

The "We Are Never Getting Back Together" singer says:

    “I wanted to share some news with you, because we’re finally making it official with one of the great loves of my life…Diet Coke."

For a second there, we thought she was gonna say Harry Styles. Bummer! As for the Diet Coke deal, Swift will be the focus of the brand's Stay Extraordinary Campaign.

The dollar figure for the partnership hasn't been revealed, but many speculate it's in the seven-figure range. Taylor adds:

    “I’ve said for years that Diet Coke just ‘gets me’ and my lifestyle. I’m so excited about our new partnership."

Sweet deal, indeed!