The 30-year-old fast bowling all-rounder has been included in a 12-man squad for the second Test against South Africa starting here at Headingley on Friday.
Although England have fielded an unchanged side for a record six successive Tests, Flintoff has been widely tipped to be in the team for the first time since captaining the side at Sydney in January 2007 in a defeat that sealed a 5-0 Ashes series loss.
Since then an injury to his left ankle, which has now been operated on four times, and, more recently, a side strain have kept Flintoff out of the five-day game.
But, having made South Africa follow-on in the first Test, the way in which the Proteas then lost just three more wickets at Lord's suggested England were missing Flintoff the bowler especially.
And the aggressive Lancashire paceman and hard-hitting batsman insisted he had no lingering doubts regarding his fitness.
"I've waited a long time, a lot of hard work has gone into the past 18 months to get back in the Test squad so I'm excited as well," Flintoff told reporters at Headingley. "It has been frustrating but there's not a great deal I could have done about it.
"I've managed to get two Championship games under my belt. I feel good about my game and fitness. The side strain is long gone, the ankle operation was that long ago, that is forgotten too."
"Obviously, I'm pleased, I'm ecstatic to be back in the England squad. It has been so long, for me it is almost a fresh start."
Asked how he maintained his morale during months of rehabilitation, Flintoff replied: "If you have ever put an England shirt on and played for England, that's enough. The excitement and emotions of playing a Test match, walking out there with the team, is enough to keep anyone going who has experienced it."
Despite his long lay-off Flintoff, the star of England's 2005 Ashes triumph and a veteran of 67 Tests, said his best was yet to come.
"I didn't start bowling properly until I was 24 or 25. I've got a bit of pace but I've got more craft. I can adapt to siuations within the game and different pitches.
"With the bat, I didn't start the season too well but over the past few weeks I feel I've made strides. Batsmen in their early 30s reach their peak, so hopefully for me it's just round the corner."
However, it was Flintoff's ability to move the ball at pace that was a major concern for South Africa coach Mickey Arthur.
"It's probably Flintoff the bowler that worries us a little bit more," Arthur, also at Headingley, said. "He bowls particularly well coming round the wicket - so our left-handers Graeme Smith and Ashwell Prince will be prepared."
"He's a quality, quality player. If we're going to conquer England and win here we want to do it against their best side - and their best side certainly has 'Fred' in it."
The out-of-form Paul Collingwood appears the most likely candidate to make way for Flintoff but Arthur said that would have an effect of England's batting line-up.
"I'm not sure who's going to be the unlucky one to lose out for England. But if it is Collingwood, Flintoff at six is going to put a lot of pressure on their top order."
But Flintoff said he didn't expect to be singled out by South Africa.
"I don't expect any special treatment, they will be going hard at us all."