Who is this woman & why do I care? Rob Kardashian's reaction to Caitlyn Jenner's photos

Kim Kardashian has revealed her baby brother was totally unaware that  Caitlyn Jenner, formerly know as Bruce Jenner, was going to reveal her female self on the cover of Vanity Fair yesterday.
Speaking at the CDFA Fashion Awards, Kim revealed that Rob didn't recognise Caitlyn when she sent him the cover shoot pictures.She told Access Hollywood

"It was so funny because all the girls - we knew Caitlyn was shooting this, but my brother had no idea,So I sent it on a mass text to everybody and my brother was on it, and he goes, "Kim, why are you sending me this? Who is this woman and why do I care?"And I was like, Rob, that's Bruce - that's Caitlyn. And he was like, "Oh my god, she's beautiful."And then he called her and they had a lovefest and it was so cute."