Khan, 27, smiled as he glad-handed fans on his walk to the stage for the weigh-in at the MGM Grand Garden Arena.
He then stripped off his blue tracksuit to his underwear before stepping on the scales in front of the 7,000 crowd.
Collazo, 33, also looked relaxed as he chewed on some gum before tipping the scales right on the 10st 7lbs limit too.
Khan said: “What a great crowd this is. This fight can take me on to bigger and better fights. But I’m not looking past Luis Collazo.”
“Luis Collazo is a tough guy who comes to fight. that’s what I will do and I believe this fight can steal the show. Both of us come 100 per cent, both are ready to go.” stated Amir Khan.
Collazo claims he is ready to compete against Khan in their clash for the WBC Silver welterweight title.
The New Yorker said: “If you have faith in God, anything is possible.
“Just focus and feel humble. this is another step towards where I want to be. I want to give fans what they want – excitement.”
Amir Khan and former WBA welterweight title holder Luis Collazo have the same goal: a win at the MGM Grand Garden Arena and then the big show against main man Floyd Mayweather next time out.