得意忘形
Leap out of one's skin.
Beside oneself with joy.
Leap with joy.
To tread on air.
Turn one's head.

eg：He is ready to leap out of his skin on learning that he has been awarded the scholarship.

中英俚语俗语来源：晋书·阮籍传：“当其得意，忽忘形骸。”

同义词：手舞足蹈 Dance for joy.