Miley Cyrus and Rihanna are known as two of music world's most popular singers... and at times they get to clash with each other.

Take it when the two battled for who gets to spend more at the amfAR Gala Auction in LA.

Rihanna spent $35,000 for a pair of Harry Winston diamond link earrings, studded by 72 diamonds set in platinum. Then, she dropped another $100,000 for an Elizabeth Taylor photograph at the Eden Roc by Willy Rizzo, autographed and numbered by the artist.

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But it was Miley Cyrus who gets the best spender of the night award, after shelling $500,000 in total.

The actress won a Ryan McGinley photograph after paying $300,000.

She then donated $200,000 to the AIDS charity.

In an interview, the "Wrecking Ball" singer admitted that she'd had a few drinks that's why she didn't know she spent too much.

"I'm a little drunk," the singer-actress said.

"That's why I'm a half a million deep," she continued. Then, she discussed about her new role as MAC Cosmetics' new Viva Glam celebrity ambassador.

Then, she talked about what she wants to do for the AIDS cause: "I would like to start an open dialogue about prevention and awareness and how people in the world have been effected by HIV and AIDS," Cyrus said.

She also hoped to "break down people's walls that have been built up around sexuality," Cyrus continued. 

TagsMiley Cyrus, amfAR, Rihanna