WASHINGTON • When United States President Barack Obama and First Lady Michelle Obama challenged Britain's Prince Harry on social media, he responded by bringing in a big gun: the Queen.
The Obamas posted a video of themselves on Twitter promoting the Invictus Games, an international sports event for wounded, disabled and sick military personnel and veterans.
"Hey, Prince Harry. Remember when you told us to 'bring it' at the Invictus Games?" Mrs Obama playfully challenges. "Careful what you wish for," the President says, as military officers stand behind the first couple with mock menace on their faces.
"Boom!" one of the guards says, dropping an imitation bomb to add emphasis to the good-natured taunt.
Prince Harry, fifth in line to the throne and a patron of the Invictus Games, responded to the US President and his wife in kind.
"Unfortunately for you, @Flotus and @Potus, I wasn't alone when you sent me that video," the prince tweeted to the Obamas at their Twitter handles.
He added a smiley face emoticon and a video of his own, showing him chatting with his grandmother Queen Elizabeth II while they look at an Invictus Games brochure, just as the Obamas' challenge lands in his mobile phone.
"Boom?" the Queen says to her grandson after watching the video. "Really, please!" she adds in amusement. Turning to the camera, Prince Harry smiles triumphantly and says, "Boom!"
The Invictus Games, first held in London in September 2014, will take place this year in the US state of Florida from May 8 to 12.
Prince Harry visited the White House in October last year when Mr Obama said the Games were a way to make sure people see not only the sacrifices wounded warriors have made, "but also the incredible contributions, strength and courage that they continue to display".
During a visit to a Virginia military base the same day, the prince issued a friendly challenge to potential US competitors: "You better bring it, USA."