In 2012,we investigated the possible molecular states composed of two charmed mesons[Phys.Rev.D 88(2013)114008;2012 arXiv:1211.5007[hep-ph]].The D*D system with the quantum numbers of I(JP)=0(1+)was found to be a good candidate of the loosely bound molecular state.This state is very close to the D*D threshold with a binding energy around 0.47 MeV.This prediction was confirmed by the new LHCb observation of Tcc+[see Franz Muheim's talk at the European Physical Society conference on high energy physics 2021].