The pair, who share two children together, stepped out last night for the Sixth Annual Breakthrough Prize Awards at the NASA Ames Research Center in California.
For the occasion, Mila wore a Dolce & Gabbana dress featuring a sheer, strapless bodice and an oversized floral skirt. Ashton complimented his stunning wife in a black suit.
Though Mila and Ashton have been married for two years, it's the first time they've walked the red carpet together since they were promoting That '70s Show in 2000.
The actors met on the set of the series back in 1998 - when Mila was 14 and Ashton was 20 - but didn't start dating until 2012.