another country heard from

Another country heard from! (yet another person adds to the conversation) — Только тебя мы еще не слышали! Ну вот только тебя (твоего мнения, твоего голоса) тут не хватало! Еще ты будешь тут выступать! Не было печали — теперь еще и ты! (любые вар-ты, выражающие недовольство тем, что молчавший человек вдруг тоже высказывается)

Used when someone joins a discussion other people are having, especially unexpectedly. {Used sarcastically, implying that the new speaker is not welcome in the discussion.}

Example 1:
Alan: You ought to take a vacation tomorrow. You really look tired.
Fred: I am not tired and I don't need a vacation.
Jane: But you do seem awfully short-tempered.
Fred: Well, well, another country heard from!
(McGraw-Hill Dictionary of American Idioms and Phrasal Verbs)

Example 2:
Brother: Let's go to the movies.
Father: I'm too busy to drive you to the movies.
Sister: I want to go to the movies, too. Let's go to the movies! Father: Oh, splendid. Another country heard from.
(McGraw-Hill Dictionary of American Idioms and Phrasal Verbs)