Brazil will be a guarantor of the peace talks between the Colombian government and the guerrillas of the ELN, the National Liberation Army.
Brasilia announced that it accepted the invitation of the administration headed by President Gustavo Petro.
The Brazilian Foreign Ministry also recalled that the country had already participated in the negotiations until 2019.
It was then that former president Jair Bolsonaro decided to withdraw Brazil from the process.
Mr Petro seeks to replicate with the ELN the peace agreement sealed in 2016 by the once largest guerrilla group in Colombia: the FARC.