The proposal happened on Saturday in Dubai, where the pair was attending the Global Gift Foundation Gala.
The longtime couple took a photo together that Longoria posted on Instagram later that evening. Longoria looked stunning in a floor-length, embellished white gown with sheer puffy sleeves, while Baston looked dapper in a suit and bowtie.
"No words for this handsomeness!" she wrote.
Just five hours before Longoria made the engagement announcement, the pair took a jaunt through the desert, where they made some furry new friends.
"Wouldn't be the #Dubai desert without the camels!" she tweeted, sharing her view.
Longoria and Baston first stepped out as a couple in November 2013. This will be the third marriage for Longoria, who was previously married to actor Christopher Tyler from 2002 to 2004 and French basketball player Tony Parker before from 2007 to 2011.