During a special Stand Up to Cancer episode of "Carpool Karaoke" on Saturday, singer Michael Bublé had a heart-wrenching conversation with James Corden about his 5-year-old son Noah's cancer battle. Access Hollywood reports Buble opened up about his hardship as a parent of a sick child and explains how it's news that no parent wants to get. Buble shares, "It's so hard to have to acknowledge it because it is so painful to talk about.