Lee Purdy is ready to turn a boyhood dream into reality when he fights for the world welterweight crown in Atlantic City on Saturday night.

The 25-year-old goes toe-to-toe with defending IBF champion Devon Alexander at Boardwalk Hall, having been drafted in as a late replacement for stablemate, Kell Brook, who suffered a foot injury last month.

The Colchester man has won his last four fights by knockout since losing a majority decision verdict to fellow Briton Colin Lynes in November 2011, but will have his work cut out against Alexander, who has also won two world titles in the light-welterweight division.

“When you lace up a pair of gloves when you’re a young boy this is what you dream of and it’s come true,” said Matchroom Boxing-promoted Purdy.

“I’m excited for the fight, I’m ready, it’s at late notice but I’m in good shape and I’ll be dangerous for 12 rounds.

“We’ve got 12 three-minute rounds and it comes to more than just skills in the pro ring.

“You need heart, you need power, you need durability to get through a long 12-round fight and I believe I’ve got all of that in abundance.

“I’m ready to fight for as long as it takes. I haven’t come all this way to America to let the fans down. I’ve come here to fight and I’m going to find a way to win.”

Purdy will be a clear underdog but, with 20 wins from 24 contests, has warned southpaw Alexander to write him off at his peril, even in the American’s own backyard.

“When me and Devon step in that ring it doesn’t matter where the ring is in the world,” he said.

“It’s a ring at the end of the day and Devon’s going to be in front of me.

“I’m in great shape and ready to put a big statement out there.”

Missouri-born Alexander, meanwhile, who is a year older than Purdy, is adamant there will only be one winner.

“Lee Purdy is coming to fight, he’s hungry, he wants my title but he is just in the wrong spot at the wrong time,” he said.

“I’m in another lane and my lane is going to superstardom.”