Adams, 35, posted a video of the proposal on the beach.
He could be seen down on one knee and then an enthusiastic Hyland, 28, leapt into his arms and kissed him.
They also shared pictures of the beautiful ring on Hyland's finger.
Hyland and Adams started chatting with each other on Twitter in 2016, and announced that they were a couple in October 2017. Adams moved to Los Angeles to be with Hyland in August of last year.
So far, there is no word yet on when and where their wedding will take place.
Hyland has played Haley Dunphy on ABC's Modern Family since it began in 2009. It will end its 11-season run in 2020.
Adams was a contestant on season 12 (JoJo Fletcher's season) of the The Bachelorette in 2016. He also appeared on the third season of Bachelor in Paradise before returning in seasons four and five as its bartender. He will continue his role as bartender for the upcoming sixth season of the show, premiering on August 5th on ABC!