LG turns 30 on Monday and she celebrated at No Name Club in Hollywood ... along with Taylor Swift, Lana Del Rey, Kate Hudson, Pharrell, Chrissy Teigen & John Legend, Lisa Vanderpump and Kathy Bates ... to name just a few.
Check out the video ... everyone raved about the party and Gaga's performance -- which she clearly wanted on the DL, since no video's popped up yet.
Best gift of the night goes to whoever showed up with a famous 1990 MJ sketch called, "Dancing Feet." Michael reportedly made a few of these ... one of which sold in 2010 for nearly $25k!
She's got friends in high places.