Top pair events provide a source of bb pairs, which can be used to probe CP violation in heavy-flavour mixing and decay. In events where one of the W bosons decays leptonically to an electron or muon, the charge of the W boson can be used to determine unambiguously the flavour charge of the accompanying b quark at the time of its production. In cases where the b also decays semileptonically to a muon, this sample allows to probe two charge asymmetries constructed with the charge signs of the W and the soft muon. The first measurement of the charge asymmetries in bb from top pair decays is hence presented using the data collected with the ATLAS detector during the 8 TeV run of the LHC.