Nip Slip

Victoria's Secret Angel Stella Maxwell -- Miley Cyrus' old hookup chick -- either broke or embraced rule number 1 by rolling up to the Love Magazine party in London Monday night braless in full boob glory.

It's one way to stick out in a crowd that included Bella Hadid, Rocco Ritchie, Kate Moss, Courtney Love and Frances Bean, Cara Delevingne and Rosie Huntington-Whiteley.

Rita Ora put her love for the good ole U.S. of A. on full display ... on her nipples.

Ora fell 48 stars short of a true American flag salute after her Wednesday night show at the El Rey Theater in L.A. -- though we doubt she heard a single complaint about it.

Perhaps next time ... Rita can take a few pasty pointers from Miley Cyrus, who definitely wore them better last night on "Jimmy Kimmel Live!"

They are a party in the U.S.A.

Chrissy Teigen thinks nipples are like the Mona Lisa ... completely overrated.

Teigen ran into our photog in Bev Hills Wednesday, telling us why she "f**ked" with Instagram this week with her bare boobie photo assault.

Clearly, C.T. doesn't think lady nips are a big deal ... and vows even MORE social media toplessness in the very near future.

In other words, she's gonna milk this controversy for all it's worth.