Former Westlife singers Kian Egan and Nicky Byrne have developed a bitter rivalry because Kian, 33, was paid ÂŁ40,000 (âŹ47,956) more to take part in ITV's 'I'm A Celebrity...Get Me Out Of Here!' earlier this month than Nicky, 35, earned for appearing on the BBC series 'Strictly Come Dancing' last year.