Diaz is taking part in his first fight in six years and weighed-in at 185.5 pounds for the five-round middleweight bout on Friday morning, with his opponent coming in at 184 lbs.
Both fighters were relaxed in a time final face-off ahead of their rematch, though it has been 17 years since the pair first met back at UFC 47 in April 2004. Diaz managed to knock out Lawler in the second round of the welterweight clash, which also took place in Las Vegas.
Nick Diaz (left) and Robbie Lawler (right) faced off for the final time before Saturday's fight
Diaz weighed in at in at 185.5 pounds for Saturday's middleweight bout, with Lawler at 184
This fight was meant to be a welterweight clash as well, though both competitors agreed to take part in the division above, due to Diaz's problems in making weight.
Diaz's last appearance in the octagon came in 2015 when his clash with Anderson Silva was deemed a non-contest after both fighters were found to have taken illegal substances in the lead-up to the fight.
The clash was initially awarded as an unanimous decision victory for Silva, though the Brazilian tested positive for steroids drostanolone and androsterone, while Diaz had traced of marijuana in his system.
Even though American fighter Diaz is making his long-awaited return to MMA, the 38-year-old is feeling conflicted about his comeback and admits he does not enjoy fighting.
It is Diaz's (left) first UFC fight since his no-contest bout with Anderson Silva (right) in 2015
'I never enjoyed fighting,' he told ESPN. 'It's just something that I do. It's just what I do. I tried to get away from it, but really it's kind of inevitable. It is. All the people around me and all the