McLaren Formula 1 driver Fernando Alonso has insisted that he is "completely fine" after spending three days in hospital with concussion.

The Spaniard underwent MRI and CT scans after crashing his McLaren at the Circuit de Catalunya during pre-season testing in Barcelona last weekend.

There were concerns over the driver's health as he has been rested from this week's final testing, but Alonso has released a YouTube video insisting that he is in good health.

The 2015 Formula 1 season will get underway with the Australian Grand Prix in Melbourne next month.