The 27-year-old has never been involved in the senior side, despite representing Spain at under-20, under-21 and under-23 level.
However, after a fine start to the season with Manchester United, which have included a good partnership with Paul Pogba, Herrera has been inviting to join the Spanish squad ahead of their World Cup qualifier against Italy at the Juventus Stadium on Thursday evening.
Herrera had seemed to give up on an international call-up until De Gea broke the news to him while he was on a break in Madrid.
"I was in Madrid, staying at a hotel in Paseo del Prado for a couple of days with my daughter and my girlfriend to enjoy the city and climate, which we missed a little bit [in England]," said Herrera.
"David de Gea called me unexpectedly and I thought he was calling me for something else.
"He said, ‘Come over here.’
"'Here? But where's here?' I replied. I didn't realise at that moment.
"'[Julen] Lopetegui told me that you will come with us,' he said.
"I thought it was a joke and even asked him if it was."
Hererra got the call after injuries to Saul Niguez and Thiago Alcantara and as he was on a short break with his family, he did not have any of his training gear, leading him to panic-buy a pair of boots.
According to Spanish newspaper El Confidencial, the former Atheltic Bilbao playmaker was given special dispensation to leave Spain’s training camp in order to purchase a new pair of boots.Reuse content