The 23-year-old has been selected by Three Lions boss Roy Hodgson for the friendlies against Chile and Germany, having made his last international appearance in the penalty-shootout loss to Italy in the quarter-finals of the 2012 European Championships.
"It's a massive boost and I'm delighted to be going there but when I'm there I need to make sure I'm working hard and do what I've been doing here really," Henderson told reporters.
"I think it [the World Cup] is up for grabs for anyone. If you are doing well and your team is doing well people will be looking at you, but now I have the chance to go and train and possibly play I have to make sure I'm at it from the start.
"I am sure a World Cup will inspire anyone but football is enough to inspire me, just to go out and play every week. Hopefully I can do the best I can and get picked again. I definitely think I have improved."
Henderson has started every one of Liverpool's 11 Premier League games this season.