How to feed lambda function's output to the lex intent as input(user utterance)?

Is there any way to send lambda function's output as the input(utterance) to the lex intent? I need my lex bot to start the conversation saying "hello" without any sample utterance/user input, and when the conversation starts, I'm running a lambda function whose output will be fed to the lex as input/utterance, then the lex has to respond to the input.