The 24-year-old played down suggestions that he is a short-tempered player and believes the Selecao must win gold at the Olympics after dropping down in the Fifa World Rankings
The full-back is one of three players aged over 23 to make the Selecao squad for the tournament in Britain, where they will tackle Egypt, Belarus and New Zealand.
Speaking ahead of the competition, Marcelo insisted he is not paying attention to critics who say that he lets emotions get the better of him on the pitch.
"I am a very joyous player on the pitch, a very happy one," he told reporters at a press conference. "Being in the national team makes me even happier.
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"If I am a hot-headed guy? When a fight breaks out, only those who are on the pitch know what it is like.
"Many people say things, but that will not get me down. If it is necessary I will give my life to the national team."
Brazil have dropped out of top 10 in the Fifa World Rankings, and Marcelo urged the team to win gold in order to recover their "prestige".
"Winning is the only way that we will get our prestige back," he noted. "I will do my best to give our fans that joy."