Testing methods of software systems have been receiving more and more focus in recent years. Exploratory Testing (ET) is one such testing method. The advantages of ET are generally outweighed by its disadvantages, mainly the time necessary to perform it. Multiple test automation methods and frameworks offer time saving benefits, in generally what is already a limited amount of time in the development process. In this study we propose Model-based Exploratory Testing (MBET), an approach that incorporates the advantages of ET and the time saving automation of Model-based Testing (MBT). To assess our approach, we conducted a controlled experiment focusing on the number, severity, and type of defects that were detected by MBT and MBET. Our results show that the defects detected by these two testing methods are complementary, and can generate a test suite that provides advantages of both ET and automated testing methods.