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Katy Perry marked her quarter-century milestone with exactly the kind of childlike exuberance you'd expect, commemorating the big day with finger paints, candy, cake flinging and oodles of Oompa-Loompas.

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It was all part of the popster's "Charlie and the Chocolate Factory"-themed blowout 25th birthday bash Saturday night at Los Angeles hot spot The Beach on Sunset, where the likes of Taylor Swift found their required all-white attire splattered in neon paint after the shindig got a wee bit wild and crazy.

RELATED: See pics from Katy Perry's wet 'n' wild photo shoot

On hand to help Katy celebrate the occasion was her budding beau Russell Brand, who played the attentive escort all evening.

"They were totally loved up!" a spy gushes to Radar Online. "Katy was having a ball and Russell was catering to her every whim. At one point he was down on his knees bowing and offering her a huge swirly lollipop. She grabbed it from his hands and pretended to knight him with it."

That was probably more enjoyable than what happened when Brand apparently refused to shake his booty, a decision that didn't sit well with the Oompa-Loompas, who Perry paid tribute to with specially designed fingernails.

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"They started humping his leg, so Katy joined in," a reveler tells the London Daily Mirror. "She was in a crazy mood. The place was destroyed."

Pictures back up that claim. In addition to the paint war, a food fight also broke out after partygoers got their hands on Perry's enormous cake with an elaborate Willy Wonka motif, which ended up smeared all over the floor of the club (see more party pics here and here).

No word on whether the shaggy funnyman followed through on his reported plan to surprise his squeeze with an animatronic petting zoo.

RELATED: Check out pics from Katy's Seventeen cover shoot

Meanwhile, rumblings have already begun about the possibility of the pair of little more than a month setting up house together. The Daily Mirror claims they're looking for a spacious pad in the Hollywood Hills with a hot tub and a yard.

"Like a lot of celebrity romances, Russell and Katy have totally dived in at the deep end, but they've completely fallen for each other," elaborates a source. "Katy's just the girl to keep Russell on his toes and he's head over heels. He keeps telling us he's never met anyone like her and he knows she's the one for him. He's 34 and has been playing the field for years now and he's thinking this could be the time to settle down."

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(Anyone taking bets on this? If so, we want in, because the odds are not in the short-attention-span swordsman's favor.)

According to the London Sun, Brand is "so smitten" that he has boldly made plans months in advance by inviting Perry to London to meet his family over the Christmas holidays.

Katy, for her part, supposedly showed her enthusiasm for her hirsute honey by hiring a skywriter to puff out the words "I Love You" over Russell's Los Angeles digs last week.

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