The pair made its first public outing since reuniting last year when they embraced on the red carpet at the Metropolitan Museum of Art's Costume Institute Gala in New York City on Monday.
Law has since opened up about the rekindled romance, admitting he is "very happy" to be back in Miller's arms.
And the Factory Girl actress is just as pleased to have reunited with Law, who she split from in 2006 after his affair with his children's nanny was exposed in the tabloids.
Hoppen says, "Sienna has never been happier. She is so content and happy with Jude. And she has never looked so beautiful. As soon as I saw those pictures of them at the Met Ball I texted her to say how beautiful she looked... When you see them together they look just as young as they were the first time around. The whole family is in a good place and doing well."