She quite literally has the key to his heart.

Jennifer Lopez's 52nd birthday celebration was certainly one to remember (and going to be quite hard to top, tbh). And now, Ben Affleck has given her a keepsake to forever remember this iconic and monumental tour around Italy.

The Gone Girl actor gifted Lopez with a very special piece of jewelry for her birthday. Affleck collaborated with luxury jewelry brand Foundrae and its designers, husband-and-wife duo Beth and Murat Bugdaycay, to create a very special necklace and collection of pendants and charms that tell the story of their love.

The necklace included key and heart pendants, as well as charms that symbolize a compass, karma, passion, and more to depict their love story, which started back on the set of Gigli in 2002. The charms are all linked together with a few different kinds of thick chains to create a layering effect.

According to The Daily Mail, the sentimental necklace cost Affleck $44,665 total. Designer Beth opened up to the Adventurine about the gift and the process of designing it.

"Ben wanted to get something really special for her birthday," she said. "He wanted to put together a meaningful story. He didn't just get her the biggest diamond he could find, he wanted to say something about their relationship."

J.Lo showed off the meaningful gift and went IG official with Affleck when she shared a series of birthday photos from her lavish trip to Instagram that included one very steamy kissing picture with her on-again boyfriend.

During the European vacation, J.Lo has been spotted wearing a nostalgic diamond bracelet from the days of Bennifer 1.0, as well as a "Ben" necklace, so it's clear that Lopez is keeping Affleck close to her heart.