From Longman Dictionary of Contemporary Englishbe in seventh heavenbe in seventh heaveninformal to be extremely happy → seventh
Examples from the Corpus
be in seventh heaven• We got Darren a puppy for Christmas, and he was in seventh heaven.• But Leonora was in seventh heaven.• He was in seventh heaven, so excited.• My good friends of masher persuasion are in seventh heaven when they have the opportunity of admiring eight pretty faces. 