Rodriguez posted a photo of the stunning ring on Instagram Saturday night with the caption 'She said yes.'
The couple has been posting pictures throughout the weekend of their beach getaway.
This will be J-Lo's fourth marriage and A-Rod's second.
They have been dating for two years and landed on the cover of Vanity Fair magazine with their celebrity couple nickname, J-Rod.
They each have two children from previous marriages.
In January, Rodriguez told The Associated Press that he and Lopez had similar backgrounds and her latest film "Second Act" reflected the ties that drew them together.
"It really resembles a lot of the arc that Jennifer and I lived in our life: Both born in New York, both come from immigrant parents, both have two children, both Latino Americano - her from Puerto Rico, me from Dominican Republic. We've been through our ups and downs, but here we are in our 40s and trying to live the best lives possible and, at the same time, give back and pay it forward," Rodriguez said.
(The Associated Press contributed to this report.)
* Follow us on YouTube
* More local news
* Send us a news tip
* Download the abc7NY app for breaking news alerts