Yes, the mom of eight and Mother Monster (we'll let you figure out who's who) are both celebrating their birthday today.
Kate is turning 36, while Gaga is hitting the big 2-5.
So how are these two partying?
Although the single mom was painting the town in NYC last week, enjoying limo service and even hitting the clubs, she was snapped wearing sweats and taking out the trash back in Pennsylvania yesterday.
Gaga is having a more glam time, natch.
She got an early birthday prezzie when she got to meet Alice Cooper this weekend.
"I just died and went to Hell," she tweeted, along with a photo of them backstage.
There's no break for the birthday girl's busy schedule.
Tonight, she performs in L.A. at the Staples Center, but she doesn't seem to mind working on her big day.
We're guessing Gaga will party after she performs with some of her famous friends.
As for Kate? She'll probably go spray tanning and have a few cosmos or something else equally crazy!