Embodiments of present disclosure relates to a voice assistant device and method for controlling the voice assistant device. The voice assistant device comprising receiver configured to receive at least one voice input from user, when operated in wake-up mode. Intent associated with the at least one voice input from the at least one user. Further, probability of issuance of a subsequent voice input from the at least one user is determined based on at least one of the intent, historic data and one or more contextual factors. An extended wake-up duration of the voice assistant device is estimated, when the probability is greater than a predefined threshold value. Further, duration of the wake-up mode is extended for the extended wake-up duration to receive the subsequent voice input from the at least one user.