Menu > Configure Map > Map Source > New:
Name: Google Earth
Url: http://mts0.googleapis.com/vt/lyrs=s&x={1}&y={2}&z={0}
Zoom: 1-18
Expiry: 259200 (0.5 year)
Every thing else: default
Now you can add as over- or underlay.
Hope you like it!
Same info in https://forum.openstreetmap.org/viewtopic.php?id=73951
Knut