The 30-year-old joined Nacional on a six-month deal after parting ways with Brazilian outfit Avai.
“I am very happy because I know I’m going to a big club whose supporters are going to be behind me,” Gamalho told reporters.
Nacional have won South America’s premier club competition three times, the last of which came in 1988.
They have been drawn in the same group as Brazil’s Palmeiras, Argentina’s Rosario Central and another team that is yet to be determined.
The tournament’s group stage runs from February 17 to April 20. Enditem