Inclusion Criteria:  aged above 18 years, diagnosed with GDM defined using fasting blood glucose > 5.1mmol/1 or 2-hour postprandial >7.8mmol/1 which are the standard guidelines for diagnosis of GDM in Malaysia, permanent resident in the state of Selangor, registered in one of the study health clinics owning a smartphone (iOS 11 or Android 7) with internet connection, able to speak, read, and understand English and/or Malay.  Exclusion Criteria:  are having a twin pregnancy, have type 1 or 2 diabetes, have severe physical disability that would prevent any increased uptake of physical exercise, have severe mental illness (psychosis, bipolar, substance dependence or active suicidal ideation), are currently participating in a weight loss program or diabetes prevention intervention.