They celebrated two years of wedded bliss in July. But Ashton Kutcher, 39, and Mila Kunis, 34, made their red carpet debut on Sunday night at the Breakthrough Prize Awards at the NASA Ames Research Center in Mountain View, California.

The last time the duo walked the carpet together was in 2000 during their time on sitcom That '70s Show.  It only took the besotted couple 17 years to do it again. 

Their hit show ran for eight years, spanning from 1998 to 2006. After Ashton's marriage to Demi Moore collapsed the two finally struck up a romance after 14 years of friendship. 

After kindling their romance in 2012 the duo got engaged in February 2014. Later that year in October they welcomed daughter Wyatt. 

Mila and Ashton got married in July the following year. And in November 2016 the two brought a second child into the world, a son named Dimitri   

Meanwhile, on Sunday night, the loving actors put on an amorous display as they giggled to each other at the event celebrating the best scientific work of the year in addition to inspiring future generations of scientists. 

Mila showed off her tanned and toned arms in a strapless gown which featured black sheer paneling along the bust.

Her gorgeous gown was worn tight around her slender waist and billowed into a satin floral skirt, with bright pink roses and green vines throughout. 

The mother-of-two tied back her long chocolate brown hair into a loose chignon and accessorized with a pair of sparkling diamond earrings. 

Ashton looked handsome in a black suit with a crisp black bow tie peeking through the collar of his white shirt.