The Essex all-rounder, who turns 28 on Saturday, was something of a surprise inclusion in a 15-man party announced by the hosts on Thursday morning, having played no part in either of the touring squads since Ashley Giles took over as limited-overs coach.
His last appearance in a 50-over international came last September, when a return of just 22 runs in four matches against South Africa saw him moved to the periphery. But, after edging out Samit Patel, Rikki Clarke and Luke Wright, he told BBC Radio Five Live: "I'm loving my cricket. I feel 16 again."
Bopara, who scored six and failed to take a wicket in Essex's Yorkshire Bank 40 defeat to Hampshire on Friday night, added: "This is a chance for me to get back in the squad and nail my spot. I had a few personal things to deal with and it probably told in my cricket at the back end of last summer. I'm glad to be back and I'm raring to go."
Bopara was arguably the only unexpected pick by England's selectors, with 14 of the 15 slots effectively settled several weeks ago.
The only other area of debate focused on the spare seamer, with Giles' former Warwickshire protege Chris Woakes getting the nod ahead of Surrey's Jade Dernbach.
Tim Bresnan and Graeme Swann were both named having come back from respective elbow injuries, but their fitness will be monitored ahead of the Ashes.
Alastair Cook, Ian Bell, Jonathan Trott, Eoin Morgan and Joe Root are the batsmen - with Kevin Pietersen previously ruled out with a knee problem.
Jos Buttler will enter the tournament as first-choice wicketkeeper, with Jonny Bairstow doubling up as reserve gloveman and an additional batsman.
Kent captain James Tredwell remains in place as Swann's understudy, while the established trio James Anderson, Steven Finn and Stuart Broad were all certain selections.