Sean Lennon, Yoko Ono and Charlotte Kemp Muhl

Singer Sean Lennon, left, Yoko Ono (who had quite a few moves of her own while watching the performances) and model Charlotte Kemp Muhl arrived sporting the night's biggest trend — hats.
Singer Sean Lennon, left, Yoko Ono (who had quite a few moves of her own while watching the performances) and model Charlotte Kemp Muhl arrived sporting the night's biggest trend — hats.
Willie Nelson — this year's most stylish man at the Grammys — topped off his performance with a black cowboy hat.
Pharrell's wide-brimmed hat, designed by Vivienne Westwood, earned its own Twitter account: @Pharrellhat.
Pharrell swapped out his ugly hat No. 1 for ugly hat No. 2 during his performance.
Madonna's son, David Banda, matched his mom with a black top hat.
Madonna styled her top hat with bold red lips.
The singer went for an all-white outfit — plus a white cowboy hat — during her performance with Macklemore and Ryan Lewis, and Mary Lambert.
Former Nirvana bassist Krist Novoselic, left, with Foo Fighters frontman Dave Grohl, went for a modern, Western-inspired look with his striped vest and black hat.
Ben Harper gave a thumbs-up to hats.
The Dream donned a black woven fedora.
In true LL Cool J style, the evening's host wore his signature beret.