Washington: Michelle Obama took to Twitter on Monday to send her husband an affectionate birthday message -- and a gentle ribbing about the US President`s graying hair.
"Happy birthday, Barack! Your hair`s a little grayer, but I love you more than ever," Michelle Obama wrote on her official twitter account, @FLOTUS.
The message was accompanied by an undated black and white photo of the Obamas as a young couple relaxing on a sofa.
Barack Obama is spending his 52nd birthday weekend at Camp David, the rural Maryland retreat made available to US Presidents.
He was to return to Washington later today.