Several researchers have found that the type of task and learners' level of L2 proficiency are major determinants of the type and amount of metatalk. This paper is the first attempt to investigate potential interactions among the type of metatalk, the type of task and learners' level of L2 proficiency. Intermediate and advanced Japanese learners of English were asked to write about how they solved one of two 'output-oriented' exercises (translation and scrambled sentence). Then both groups received explicit feedback in the form of correct solution. Following this, both groups wrote about their thinking processes when they had received the feedback. In the written reflections about how the participants solved the exercises, there was an interaction between the type of exercise and level of L2 proficiency for both intermediate and advanced groups. In contrast, the type of exercise was the major determinant of the type and amount of the written reflections on their reactions to the feedback. These findings provide empirical support for the Output Hypothesis, and have pedagogical implications for the choice of output-oriented grammar tasks.