The app, Tesco Calling Card, lets customers avoid expensive roaming charges by making international calls via a Wi-Fi connection, with cheap charges that start from a penny per minute (with no connection fee).
Users get £1 worth of free credit when they download the app, so you can give it a whirl for nothing – and extra credits can be earned by referring friends to the service. Also, app to app calling and messaging is free full-stop.
Rates vary, naturally, depending on where you're calling, and whether you're ringing a landline or mobile. Calls to the US, for example, are two pence per minute in both cases, but Brazil (should you fancy ringing someone over there for the World Cup) is 2 pence per minute for a landline, or 10 pence per minute for a mobile.
Looking at reviews on the app stores, it seems there have been some teething issues initially – as ever – but they would appear to be mostly sorted, although we did spot a complaint regarding dropped connections.
Tesco is certainly serious about stepping up its efforts on the technology front. Earlier this year, the supermarket made its 4G service free for mobile customers (in the vein of Three), and it plans to follow its successful Hudl tablet up with a sequel, and an own-brand smartphone according to the rumour mill.