The 43-year-old retired MLB star showed off a picture Thursday on Instagram that Lopez autographed for him nearly 20 years ago.
"#TBT to almost 20 years ago when a big time global pop superstar signed a pic for a young ball player #lifecanbeafunnythingsometimes #pictureperfect #keepsake #jlo," Rodriguez captioned the post.
Lopez shared the same photo on her own account.
"Wow!! Had to repost!!! He found this cleaning out storage!!" she wrote.
"I turn around and I do not recognize this person," the star said. "And it's Jennifer, but she's dressed up as Harlee from Shades of Blue."
"She said, 'It's Jennifer.' I go, 'Oh my God, Jennifer, you look beautiful.' I was so embarrassed and then I got a little nervous," he recounted. "She says, 'You have my number, reach out.' And I went home that night and reached out."
Rodriguez is parent to two daughters, 13-year-old Natasha and 10-year-old Ella, with Cynthia Scurtis, while Lopez is parent to 10-year-old twins Emme and Max with Marc Anthony. The couple celebrated Lopez's birthday as a family in July.