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No, it's not the pregnant one, or the one who's married to the ball player, or the one who divorced the other ball player, it's Rob, the youngest of the Kardashian clan, who has reportedly been dating Roc Nation singer Rita Ora behind closed doors.
The New York Post claims that the 'Dancing with the Stars' finalist, 24, has been dating the 21-year-old Kosovo-born, U.K.-raised singer for several months, after they were set up by rapper Romeo, though the only evidence of their relationship is some scant exchanges on Twitter.
The Post claims that even Rob's older sisters are not aware of his relationship with Ora, who shuttles between her home in London, and the U.S.
"Rob lives a life separate to the girls and is definitely a ladies' man," explains the Post's source. "But he wouldn't have more then one [woman] at a time. He's a good boy."
Rob and Rita will allegedly be making their public debut as a couple at the Dream Downtown later tonight (Dec. 8), where Rob will be DJing an event for Macy's active-wear line, Ideology. Rob has previously been tied to Disney actress Adrienne Bailon, who appeared with him on his family's popular reality show 'Keeping Up with the Kardashians,' until the couple split in 2009.
Secrecy is nothing new for Ora, who signed a similarly hush hush deal with Jay-Z's Roc Nation in 2009, when she was just 19, and had a cameo appearance in Hov's video for 'Forever Young.' She also starred in Drake's video for his 2010 smash 'Over.' Her debut album is likely to be released some time in 2012.
Reps for the singer and reality star have declined to comment regarding their alleged affair.