The event was held by England sponsor Vauxhall and saw Southgate announce the group of players which will travel to Czech Republic before defender Ben Gibson gave viewers a private tour of St. George's and its facilities where the squad will be preparing for the Euros.
And as the team began their training session, viewers could watch live from the St. George’s Park pitches to see how the team are preparing ahead of the summer tournament.
"It is great to be able to give England fans around the country an insight into our preparations ahead of this summer’s European Under-21 Finals and also provide an opportunity to see the world-leading facilities at St George’s Park," said Southgate, ahead of the squad meet-up.
A panel, including former England goalkeeper David James, also analysed and discussed the confirmed England squad and their upcoming campaign live on the Vauxhall Google+ Hangout.
Cheryl Stibbs, Vauxhall Sponsorship Manager, said: "We’re extremely excited to be able to watch Gareth reveal his final squad live on a Google+ Hangout to millions of people around the world.
"It’s going be brilliant for fans to get an insight into the team prior to the tournament and we’re grateful that Gareth has allowed us access to be able to bring the squad announcement closer to the fans than ever before.
England will also play their final Euro warm-up game in a Vauxhall International at Oakwell when they face Belarus on Thursday 11 June. Tickets for that game are on sale now, priced at £10 and £5. Call 0871 2266777 or e-mail boxoffice@barnsleyfc.co.uk for more details.
Southgate’s side start their Euro campaign against Portugal in Uherske Hradiste on Thursday 18 June.