At the beginning of the Season 6 cliffhanger, "Descent, Part 1", Data is seen playing poker with holographic depictions of Stephen Hawking, Sir Isaac Newton, and Albert Einstein. Hawking portrayed his own hologram for this episode, making him the only guest in any Star Trek series to play himself. When taking a tour of the set, he paused at the Warp core, smiled, and said, "I'm working on that."