The 35-year-old actor's fiancee Charlotte Riley heard that meeting Hardy was on 23-year-old fan Kayleigh Duff's wish list, and helped arrange the special day, reported Daily Star.
Hardy enjoyed lunch with Duff, who is on a break from her cancer treatment, and she was left stunned when the actor gifted her with a sparkling neck piece.
"I nearly died when I saw him. I was shaking - I just thought we were having a day out in London. Tom's fiancee Charlotte and (friend) Katie arranged it all without me knowing and he was so lovely and down to earth. We had lunch and tea and scones and he bought me a diamond necklace,' she said.