The commander of the Afghan opposition, Ahmed Shah Masood, is due to meet members of the European Parliament at Strasbourg in France.
On Wednesday he had talks with the French Foreign Minister, Hubert Vedrine, in Paris.
The visit is a major propaganda coup for the Afghan opposition and has infuriated the ruling Taleban militia.
Mr Masood will not address the whole European Parliament, but he will have talks with a number of key members representing all the main political groups.
He will also hold a news conference at which he will have the opportunity to make an impression on the wider European public.
The European Parliament has very little power to influence the foreign policies of the European Union's member governments, but it does provide an important forum for debate.
The parliament's president, Nicole Fontaine - who issued the invitation to the Afghan opposition leader - has called the Taleban regime "infamous and criminal", particularly with regard to its treatment of women.
It had, she said, banished itself from the civilized international community.
So Mrs Fontaine and her fellow European parliamentarians will be keen to learn from Mr Masood how the world community might assist in efforts to oppose the Taleban.
But the Taleban itself has complained that European support for Mr Masood will merely prolong Afghanistan's civil war.
It has certainly been a significant boost to opposition morale that might also persuade the Taleban of the need to do more to extinguish this source of annoyance to their regime.
The Teleban have said that European support for Mr Masood will merely prolong the civil war in Afghanistan.