By far the best answer given above for your discrete situation is:
"He broke the news"
--"Dropping the bomb"--idiomatic at best, only useful if the information shared will likely be a large (usually upsetting) surprise/ultimatum to the receiver.
--"Spitting out" implies unwillingness on the part of the spitter to share the information, whether or not it is secret information--it implies force of words or brief words but not willingly. In past tense, it is also used to imply something completely different--disgust. (i.e. "You're disgusting!", she spat.)
--"Blurt"/"Spilling" carries the opposite connotation to "spitting out"-- that the speaker can't wait to get it out, but a blurt is often unintentional or uncontrolled, and the author is passing minor judgement on the speaker for being unable to control themselves. It's used of immature speakers (ie children) or overly impulsive speakers, people who can't stop talking or control their words, not just the sudden ones.
What you want to get across is that the news is suddenly shared.