Michelle Obama Turns 50

Tweets picture of AARP card

Michelle Obama is celebrating her 50th birthday Friday.

The first lady is spending the day out of sight, with no public appearances after back-to-back White House events this week.

But she tweeted a picture of herself holding up her AARP card. She tweeted, quote, "Excited to join Barack" in the 50-plus club today. "check out my @AARP card!"

President Barack Obama turned 50 in 2011.