Chicago Cubs slugger Anthony Rizzo showed off his tender side on Saturday when he assisted lifelong fan, Steve Milsap, with a surprise marriage proposal.

Earlier in the day, the red-hot Rizzo, who is hitting .373 in the month of May for the first-place Cubs, smashed a three-run homer in an 8-2 win over the Pittsburgh Pirates. But even more unforgettable than the game was what happened that same evening at the Fanatics sports memorabilia show in Chicago.

Show organizers had arranged for Milsap and his girlfriend, Leslie, to meet Rizzo for a photo op and autograph signing. The unsuspecting girlfriend was told that the special Rizzo meet-and-greet was a surprise was for her nine-year-old daughter, who idolizes the 26-year-old phenom.

After posing for a few photos with the family, Rizzo turned to Milsap and said, "Steve, do you have any questions you want to ask."

Milsap took a step toward his girlfriend and said, "Leslie, from the day that I met you I knew you were the one."

"No," said Leslie.

"Yes," countered her smiling boyfriend. Then he pulled a ring box from his pocket, went down on one knee and popped the question.

"Will you marry me?" he asked.

"Yes. Oh my, God. Oh my," she answered, as memorabilia show onlookers shouted their approval.

Rizzo then presented the couple with a Cubs jersey with the words "Marry Me" and Rizzo's number "44" embroidered on the back. Milsap asked if Rizzo would sign the jersey and he was happy to oblige.

The 6-foot-3, 240-pound athlete seemed to love his role as Cupid. "She was really excited and she started crying," said Rizzo. "It's awesome for them."

"I'm still in shock right now," said Leslie.

Milsap thanked Rizzo and the show coordinators.

"We couldn't have done it without Fanatics," said Milsap. "We want to thank everybody who helped out. It was amazing."

Check out the heartwarming 67-second video here...