There's no word on when the engagement happened, but the 47-year-old actor was first photographed getting cozy with his new lady love last February in Rome, according to People magazine.
This will be the third marriage for the "Labor Day" star, who has been busy at work as of late. Brolin has three movies out this year, including a cameo in the blockbuster "Avengers: Age of Ultron," which is part of his ongoing arc as the mighty villain Thanos.
"Diane Lane and Josh Brolin have decided to end their marriage," their reps confirmed to ABC News.
Brolin was married once before that and has two children -- Trevor, 26, and Eden, 20.