European Union leaders will officially designate Mr Javier Solana as the bloc's future first foreign minister when they reappoint him as foreign policy high representative today, an EU source said.
The move means the former Spanish foreign minister and Nato secretary-general will automatically become vice-president of the European Commission and run its large external relations budget and staff once a new EU constitution is ratified.
The source said the move was part of a package deal under which a special EU summit will nominate conservative Portuguese Prime Minister, Mr Jose Manuel Durao Barroso, as European Commission president from November 1st.
Frenchman Mr Pierre de Boissieu will be reappointed to the powerful post of deputy secretary-general of the EU Council, in charge of the secretariat that supports policy-setting meetings of ministers and national officials.
Mr Solana's main achievements have been in helping broker a peace deal that averted an ethnic civil war in Macedonia in 2001 and working out constitutional arrangements to keep Serbia and Montenegro, the remaining former Yugoslav republics, together in a grudging but loose union dubbed "Solania".
He has also given the EU a higher profile in Middle East peacemaking.
Mr Solana's designation as future foreign minister means Spanish European Commissioner Mr Joaquin Almunia would have to leave the Commission when the constitution takes effect, since each member state may have only one Commission member.
Mr Almunia has been in charge of economic and monetary affairs since April, but it is not clear what role he will hold in the new Commission, which takes office on November 1st.