The US First Lady Michelle Obama surprised the children on Friday by answering their calls to a NORAD - North American Aerospace Defence Command - hotline which keeps track of the gift-delivering progress of Santa Claus around the world.

According to a statement from the White House, Michelle Obama spent around 40 minutes talking with children who called hotline at NORAD - a US and Canadian military organization for aerospace and maritime defense which uses radar, satellites, high-speed digital cameras as well as fighter jets for tracking Santa.

Michelle Obama's participation - which pleasantly surprised the children who called up to the NORAD system to ask about the whereabouts of Santa - in this year's Santa-tracking proceedings is apparently the first such involvement by any US First Lady, ever since the NORAD began keeping tabs on Santa's movements in 1955.

While helping out with the hundreds of thousands of calls to the NORAD hotline, Michelle Obama - who is currently on a 10-day vacation to Hawaii with her husband and their two daughters - assured the callers that Santa's journey "was going well this Christmas Eve."

The children who quizzed the First Lady about life in the White House and President Barack Obama were 10-year-old Austin Futch from Memphis, Tennessee, and Juliana, of Goose Creek, South Carolina. Initially, they thought Michelle Obama's voice at the other end was probably a prerecorded message, but soon realized "wow, it really, really is her!"