The 31-year-old, who was handed his international debut in the friendly against Scotland in August, was featuring in the League Two play-off semi-final for Bristol Rovers against Lincoln only seven years ago.
The Southampton striker scored within moments of coming on as a substitute in the match against Scotland and went on to score 16 goals in all competitions for the south coast side during the Premier League season.
Lambert admits his inclusion in Hodgson's 23-man travelling party for Brazil has capped a remarkable rise for him to the top of the English game.
"It's hard to take in really," Lambert told Sky Sports News on Monday. "I found out about 12 o'clock today and as you can imagine it was a dream come true.
"I've felt sick over the last 24 hours - I've been nervous and anxious but I finally got the call that I am in the 23 and obviously I am over the moon to say the least.
"It's been a hell of a journey, my career as a whole.
"There have been so many ups and downs but the way it has gone over the last five years I could never have dreamed this. Especially the last year or so with England.
"Each year it has been getting better and better and now it has been topped off by getting called up by England for the World Cup."
Lambert was joined in the squad by Southampton team-mate Luke Shaw and club captain Adam Lallana.
And the striker believes Lallana, who has been heavily linked with a move to Liverpool in recent days, is a definite contender for a place in Hodgson's starting line-up for England's opener against Italy on June 14.
"It's full credit to Southampton and it shows you how well they've been doing over the years bringing through young lads," Lambert said.
"I was very confident that Adam (Lallana) would get in and to hear that Luke Shaw has got in as well is absolutely superb news and I'm delighted.
"It is unbelievable the way Adam has progressed each year and now he has gone to a whole new level.
"He's the captain and he's pushed everyone on. He brings so much more than just his ability it's also his attitude and his desire to win.
"It's brilliant to see him do so well at the minute and he's done so well that people are talking about him being in the starting line-up. I think if he is then he fully deserves it."