bruce jenner 's sitdown interview with diane sawyer airing in which he is expected to talk about his gender transition that the 30-second clip opens with the 65-year-old former decathlete greeting sawyer at his home .
bruce - the ex-husband of kardashian matriarch kris jenner - appears somewhat anxious as he tells the sawyer : ` it 's going to be an emotional rollercoaster , but somehow i 'm gon na get through it .