An astronaut named Tracy Caldwell Dyson likes to sing the Garth Brooks song, "The River" on the launch pad before heading off to space. They got to know each other last year when she gave him a tour of NASA.
So on Monday he invited her to join him for an episode of his Facebook series, "Inside Studio G". He was checking out his new stage the day before his appearance at Rodeo Houston. (The show was last night.)
Here is the video. The NASA stuff starts around the 6:00 minute mark. The launch pad clip of her singing is at 6:27. She joins him live at 6:52. They do the duet at 7:23.