Both JLo and A-Rod posted photos of the former baseball player holding her hand, adorned with a massive diamond ring.
Lopez's nails were painted white and it looks as though there is a romantic bonfire going in the background.
Rodriguez captioned his Instagram post: "she said yes".
The couple is on holiday in the Bahamas, from where they have posted snaps of white sand beaches, palm trees and warm weather.
The pair, dubbed "J-Rod", first appeared on the red carpet as a couple at the Met Gala in May 2017.