The 'Diamonds' singer looked gorgeous in double denim as she watched the action unfolding at Madison Square Garden on Friday (9 January).
According to E! News, the unlikely pair struck up quite a friendship during the night, with Jake sharing his boxing expertise with an impressed RiRi.
A source said: "Jake and Rihanna were talking and laughing during part of the matches. It was cute. He was explaining what was going on to her and she seemed very interested in the fight."
The duo certainly looked like they were having a good time as cameras caught them chatting and sharing plenty of laughs throughout the night.
Rihanna was there to support her mentor Jay Z as it was his protégé Andre Ward in the boxing ring. Andre's just been signed to Jay's Roc Nation label.
She later posed alongside a very proud looking Jay after the match.
The event, Roc Nation Sports Presents: Throne Boxing at The Theater, was organised by Jay's company.
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