Eamonn McCormack/WireImage; Sony Music EntertainmentJust a couple weeks after Rihanna was spotted sitting cozy with Chris Brown at one of Jay-Z's Barclays Center concerts in Brooklyn, New York, there's word that Hova is keeping an eye on Rih's ex. 

British tabloid The Sun reports that Rihanna's RocNation boss Jay-Z stepped into the role of protective big brother, warning Chris that he'll "finish him" if he ever hurts Rih again.  Jay's willing to give Chris a second chance though, if it's what Rihanna wants.  A source tells The Sun, "Jay-Z told Rihanna that if Chris is truly making her happy then to go for it."

The Sun adds that Jay actually invited Rih and Chris to attend his Barclays Center show.  The event reportedly gave Jay a chance to have a private, man-to-man chat with Chris backstage, ensuring the singer that he'd end his career if Rihanna was harmed physically or emotionally.

In other Rihanna news, she's unleashed a lyric video for her "Diamonds" single.  The song is set to appear on Rih's upcoming album, Unapologetic, which is due out Nov. 19.

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