Guests were told to come in fancy dress.

客人们已被告悉应穿着化装舞会服装赴会。

《柯林斯英汉双解大词典》

Dale also found international fans for his dressing up too, as each day Carol took photo of her husband in fancy dress and posted it on their blog which became a hit on the Internet.

戴尔也因为他的打扮找到了国际粉丝，因为卡罗尔每天都给她丈夫拍他穿着奇装异服的照片，并把照片发布在他们的博客上，这在网络上引起了轰动。

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We cannot believe he didn't tell us we could come in fancy dress.

我们真不敢相信他没告诉我们可以穿着奇装异服来。

youdao

At a black-tie event, the men dress in tuxedos or dark suits and the women wear fancy dresses.

VOA: special.2009.12.28

but also I think they're excused to dress up in fancy clothes

但是，我觉得他们是要借此机会盛装打扮一下，

英国皇家赛马会 - SpeakingMax英语口语达人

The New Year's Day dip, organised by the Panama Swimming Club at Whitley Bay, regularly attracts a host of people in fancy dress costumes.

BBC: North Sea dippers see in new year at Whitley Bay

Some 40, 000 spectators clad in fancy dress will pack out the Hong Kong Stadium for the three-day annual event, held 23 to 25 March this year.

BBC: Rugby, and a party, in Hong Kong

Zeta Jones will lead the parade through Harvard Square in fancy dress on 10 February, followed by a presentation and a question and answer session with the actress.

BBC: Zeta Jones won a best supporting actress Oscar for Chicago