The 18-year-old pop singer was picked for the job by designer Christopher Kane, according to The Mirror. He has already posed for some snaps taken by photographer Simon Harris.
"I couldn't believe it when I saw the pictures," said the reality TV star. "I really enjoyed the shoot. It will be so exciting to do this alongside my music."
A Next Models spokesperson said: "Not only does Joe have those classic James Dean-type looks but he also photographs fantastically and has great potential. We are already in talks with two major British designers who are keen for Joe to front campaigns."
McElderry is expected to release his debut album on Simon Cowell's Syco label in the autumn. He has also expressed an interest in working in the West End.