The Bourne Identity star's boyfriend popped the question on Christmas Eve (24Dec15) while the couple was on vacation in Isla Grande, Colombia, her representative confirms to

The 34-year-old broke the news to fans herself by sharing a sweet photo of her ring on Instagram on Monday (04Jan16).

"Best Christmas Ever!" she captioned the snap, in which she had her fingers entwined with her new fiance's.

The couple met last year (15) on the set of upcoming thriller Go With Me. Preston recently worked on Leonardo DiCaprio's The Revenant.