LAS VEGAS - Amir Khan is hungrier than ever to step back into the ring, saying he didn't want to come off the longest break of his career against an easy opponent. The 27-year-old Briton will end a 12-month hiatus on Saturday when he moves up in weight to face American Luis Collazo in a non-title fight at the MGM Grand Hotel and Casino. "I fight everyone," Khan says. "Collazo is a mixture of a boxer and a fighter. He is slick and he knows how to fight. I am a similar style so that is what is going to make this fight exciting."Khan and Collazo's 12-round welterweight fight is on the undercard of the Floyd Mayweather-Marcos Maidana 147-pound (67 kg) world title fight. "He is going to give it 100 percent and he is in great shape," Khan said Thursday at a news conference Thursday at the Hollywood Theatre in the MGM Grand. "He will be bigger than me on the night of the fight and at times I will have to dig deep." Size and weight will be crucial for Khan in his first welterweight bout."I have not ate my way up to this weight. I trained my way up to this weight," Khan said, adding that he's more comfortable at 147 pounds because he doesn't have to starve himself to get down to 140 ahead of Friday's weigh-in. I feel so much stronger and happier at this weight," he said. "That seven pounds makes a big difference and I have kept all my power and speed."Khan's last fight was in April of last year when he won a 12-round decision over Julio Diaz in Sheffield, England. Just over a month later Khan got married and now the couple are expecting a baby. After the win over Diaz, Khan took four months off from boxing to spend time with his bride. Khan (28-3, 19 knockouts) says the time away was good for him mentally and physically. "My body needed a break," he said.Khan, who turned pro in 2005 after winning a silver medal for Britain in the Athens Olympics, is one of the most exciting fighters in the sport always willing to go toe-to-toe with his opponent. "I am the most exciting fighter in the world," Khan said. "My hand speed is explosive. "When I go into the ring I give it my all, and I have been in with the best." Before the break, Khan was also one of the busiest fighters, especially for the first six years of his pro career.When he did finally return to the gym eight months ago it was a little different because instead of focusing on an upcoming fight, he just worked on conditioning and fine-tuning his craft. "I had to work on my own style and on things by myself," Khan said. "This training camp has gone really well. I have been working really hard. Even though I haven't been in the ring in the last 12 months, I have been in the gym training for eight months."In July, 2012, Khan lost to Danny Garcia in a fight for the World Boxing Council super lightweight crown. It was his second straight defeat, following a controversial loss to Lamont Peterson. A rematch with Peterson was scuttled when Peterson failed a pre-fight drug test. "Every time I've been knocked down I got back up again," Khan said. "I have been stopped on my feet but that is just boxing. I've never been knocked out." Collazo stood on the podium at Thursday's news conference and said Khan is in for a surprise in his first fight as a welterweight."Welcome to the welterweight division," said Collazo, 33. Collazo (33-5, 18 KOs) grew up selling drugs on the streets of Brooklyn. He turned pro in 2000 and won his first world title five years later. He also compiled an impressive 97-7 record as an amateur. "You're going to see the best Collazo you have ever seen," said Collazo who has been with his trainer, Nirmal Lorick, since he was 12. Saturday's undercard also features a non-title super lightweight fight between Americans Adrien Broner and Carlos Molina.