Prince Harry has enlisted the help of his grandmother the Queen in what appears to be an escalating trans-Atlantic face-off between the Prince and Michelle and Barack Obama over the Invictus Games, which are to be held in the US next month.
Earlier, the Obamas posted a video challenge to Harry on the First Lady's Twitter account.
In the video, the Obamas stare deadpan into the camera, as Michelle Obama says: "Hey, Prince Harry, remember when you told us to 'Bring It' at the Invictus Games?"
Mr Obama then says: "Careful what you wish for."
As the video comes to an end, a man dressed in a decorated military uniform standing behind the Obamas can be heard to say "Boom!", and mimes a 'mic drop'.
In the Royal response, the Queen appears to watch the video and comments disdainfully: "Oh really? Please."
Smiling at the camera, Prince Harry then mimes his own 'mic drop'.
The Prince had earlier hinted at a possible response to the Obamas, tweeting "You can dish it out, but can you take it?"
The Invictus Games, which is for injured, wounded and sick servicemen and women and veterans, began in London in 2014.
It is to take place this year between 8 and 12 May in Orlando, Florida, where both Harry and Michelle Obama will be present.
A third Invictus Games will take place in Toronto, Canada in September 2017.