Rees lost his WBA belt a year ago to Andriy Kotelnik
Ex-light-welterweight world champion Gavin Rees has been released from his contract with Frank Warren's Sports Network to join Calzaghe Promotions.
The Welshman, who lost his WBA belt to Andriy Kotelnik in March 2008, will make his Calzaghe Promotions debut in their second show on 2 May.
Rees has been trained by Enzo Calzaghe - father of retired unbeaten champion Joe - since the age of nine.
"I'm determined to prove I haven't lost it," said Rees.
Meanwhile, Rees' stable-mate Bradley Pryce, the one-time light-middleweight Commonwealth champion, has been also been released by Warren's Sports Network company.
Richard Maynard, Sports Network's press officer, said Pryce had been released from his management contract with Warren's company but they still retained their promotional agreement with him.
However, Warren told the Western Mail and South Wales Argus that both Pryce and Rees were "free to do whatever they want now" and "wished them the best for the future."
Rees, the 28-year-old whose defeat to Kotelnik is the only blemish on his professional record, is now waiting to find out his opponent will be in his first fight for 14 months at the show in Merthyr Tydfil.
"I'm going to need a warm-up somewhere and then after that I've got to get back into the title fights," he said.
Rees is now moving back down to lightweight and is desperate to "make an impact."
"I want to fight my way back up to British, European and hopefully world level," said Rees.
"But I need a few fights to get me back in the groove because if you're ring rusty against a sharp world title contender then you could be in trouble."
Meanwhile Pryce said on Tuesday he would soon be featuring on a Calzaghe Promotions bill.
Pryce said he had had a difficult year, most recently knocked out by Matthew Hall for the Commonwealth light-middleweight title in March.
At a news conference, he put his defeat down to an eating disorder, which he said he had now overcome.
He said he enjoyed junk food and in the four weeks leading up to the fight with Matthew Hall, he had been managing his weight by eating and drinking what he wanted, then vomiting.
"I got into a habit," he said. "I shouldn't have done it."
He said when he stood on the scales for the pre-fight weigh-in, his legs were buckling and he was then unable to recover in time.
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