The Look Who's Talking actress looked fab as she left a taping at the Today show in Manhattan on Monday morning (5 January).
Kirstie, 63, flaunted her new figure in a tight black dress with a plunging neckline, teamed with an open black jacket and heels.
The star's been open in the past about her struggles with weight and fluctuating between sizes.
She had promised to lose 30lbs by 2015 but ended up losing a massive 50lbs instead.
Kirstie showcased her sleek new look on Today, revealing she lost weight over the festive period rather than gaining any back.
She is a paid spokesperson for Jenny Craig and said she utilised their personal consultant service – available to everyone – to help plan out meals and exercise.
When asked about maintaining her current size, she said: "Before I've had more of a view of get to the goal, have the goal, this time I thought, 'What is the goal and timespan of the goal?' I really looked at it as, 'This is my life and until I'm dead I am going to keep this way' instead of, 'Oh, I lost 50lbs and now I can do what I want…'
"My goal is to keep this and maintain this throughout my life, especially as an actress. I'm more responsible than I was before."
As for whether her weight has been overshadowing her work as an actress, Kirstie joked: "Well, that might be a good thing!"
She added: "I want to do more acting and more movies and how do I like to see myself on film… I like to see myself looking more svelte, that's just the truth of it."
Reveal is now on Google Plus! Join us here for the latest pictures, fashion and celebrity news!