Sen. Claire McCaskill, D-Mo., rocked out to Lady Gaga on Saturday night in Saint Louis.

The "young at heart" senator tweeted that she attended the event with her husband, sister and brother-in-law, all spanning the ages 59 to 75.

"Not so little, but kinda old monsters," she tweeted.

One of McCaskill's followers snapped a shot of the senator in the crowd rocking a denim jacket. Baby, she was "born this way."