Instagram / @madonna

Madonna Dancing for Debut Album's Birthday ... Good Sign for Recovery

Madonna is movin' and groovin' on camera for the first time since her serious bacterial infection sent her to the ICU ... dancing to one of her hits on a very big career milestone date.

The 64-year-old singer was breaking it down Thursday to her track, "Lucky Star" -- the first song on her self-titled debut album, which she's wishing a happy 40th birthday.

Madonna says, "To be able to move my body and dance just a little bit makes me feel like the Luckiest Star in the world!" She goes on to thank all her fans, saying they're pretty lucky, too.

She's seemingly recovering really well, based on those moves -- as we reported, Madonna was in a battle for her health after an infection and being unresponsive and intubated in the ICU.

She got out of the hospital, and we saw her earlier this month out and about in NYC -- she also broke her silence on her medical crisis by letting her fans know she'd have no choice but to push back the start of her world tour ... which was set to start this month.

But, if this new vid is a sign, she's making great strides!

Click here for info about our online advertising practices.