US first lady Michelle Obama fielded calls from awed children when she joined a Santa-tracking switchboard on Christmas Eve.
A telephone link from Hawaii, where the Obamas are spending Christmas, allowed her to pitch in with volunteers at Peterson Air Force Base, Colorado, who were answering phone calls and emails for the North American Aerospace Defence Command's Santa-tracking programme.
"I was ecstatic because I was talking to the president's wife," said Evan Race, 10.
"I was really surprised," said his eight-year-old sister Anna. Seven-year-old Colin Race also got to talk with Mrs Obama.
The White House said Mrs Obama took calls for 40 minutes and spoke with children from at least a dozen families.
It is believed to be the first time in the 55-year history of the event that a first lady joined in, said Jamie Graybeal, Norad's deputy chief of staff for communications.
Norad Tracks Santa, the official name of the programme, began in 1955 when a Colorado Springs newspaper advert invited children to talk to Santa on a hotline.
But there was a mistake in the printed phone number and dozens of youngsters ended up dialling the Continental Aerospace Defence Command in Colorado Springs, the predecessor to Norad.
The officers on duty played along and began passing on reports of Santa's progress. It is now a cherished ritual at Norad, a joint US-Canada command that monitors the North American skies and seas from a control centre at Peterson.
"It's really ingrained in the Norad psyche and culture," said Canadian Forces Lt Gen Marcel Duval, the deputy commander of Norad, who pitches in to field French-language calls on Christmas Eve.
"It's a goodwill gesture from all of us, on our time off, to all the kids on the planet."
Last year Norad Tracks Santa answered 74,000 calls and 3,500 emails, and organisers expected to top that this year.
Although the programme is aimed at children, the volunteers answering the phones have a welcome bit of news for parents too - Santa won't stop at homes unless all the kids are asleep.
It takes four months of planning to marshal the 1,200 volunteers, 100 telephones, 30 laptops and two big projection TV screens the exercise requires, Norad spokeswoman Joyce Frankovis says.
All the labour is voluntary, with Google, Verizon, Air Canada, defence contractor Booz Allen Hamilton and others chipping in.
Yesterday volunteers answered calls and emails in two conference rooms in a building not far from Norad's headquarters. In a separate room, a three-member team fired out tweets and Facebook updates, checking against a schedule marked with a secrecy warning that said "Santa's Eye Only".
Civilian and military staff wore blue Santa hats with "Special Operations Elf" written on the white trim.
"It is tremendously fun," said Jim Jenista, Norad's deputy chief for joint training exercises who has been volunteering on the phones for nearly a decade.
Norad insiders drop hints about how they track Santa - "ultra-cool, high-tech, high-speed digital cameras", radar, satellites and Canadian Forces fighter jets.
But any inquiry into the technological particulars is met with a polite rebuff and a cryptic explanation involving the magic of Christmas.
The Norad tradition is one of the few modern additions to the centuries-old Santa Claus story that have stuck, said Gerry Bowler, a history professor at the University of Manitoba and the author of Santa Claus: A Biography.
Most embellishments never capture the public's imagination because they tend to be ad campaigns or movies that try to "kidnap" Santa for commercial purposes, Prof Bowler said.
Norad, by contrast, takes an essential element of the Santa Claus story - his travels on Christmas Eve - and looks at it through a technological lens, which brought Santa into the 20th century, Mr Bowler said.
And into the 21st century. Norad Tracks Santa now has a Twitter account, a Facebook page, a YouTube channel and apps for mobile phones, along with a website, www.noradsanta.org, and the phone line.
Occasionally an email or phone call pleads for help. A girl from Australia wrote yesterday to ask if Santa could help doctors cure her younger brother's cancer, adding that she feared he might not live until next Christmas.
Those requests are handled "with as much hope and optimism as we can", said Mr Graybeal. "We promise to pass on these emails to Santa."