The presidents of Serbia and Kosovo headed into talks in Brussels on Wednesday, the first such top-level meeting since Pristina unilaterally declared independence in 2008.
EU foreign policy chief Catherine Ashton, who is hosting the historic encounter, met separately with Serbian President Tomislav Nikolic and then Kosovo leader Atifete Jahjaga before bringing the pair together.
"This has been talked about for months. The handshake will be highly symbolic, very important," said an EU diplomat who asked not to be named.
A statement from Ashton is expected at around 1900 GMT, her office said.
Though no concrete announcements are due, the meeting marks a new and significant step in two years of efforts by the European Union to ease tension on its Western Balkans doorstep, Europe's last trouble-spot.
"Excellent that presidents of Serbia and Kosovo will see each other today. Facilitated, needless to say, by EU," tweeted Sweden's Foreign Minister Carl Bildt.
The meeting comes nearly 14 years after the end of the 1998-1999 conflict between Kosovo's ethnic Albanian separatist guerrillas and Belgrade as Brussels works to normalise ties between the pair.
Serbia, along with five of the 27 European Union nations, still do not recognise Pristina. Neither do many of the 40,000 ethnic Serbs living in northern Kosovo.
"We are dedicated to this process and firmly determined not to pass all the animosities of the past to younger generations," Jahjaga has said of efforts to ease the mutual strain.
Analysts say the meeting is more important for ultranationalist-turned-conservative Nikolic who, before his election in May 2012, was a fierce opponent of dialogue with Pristina.
"I think Nikolic is not very happy to go to Brussels, but the EU and the United States are determined to see this meeting take place," said Belgrade political analyst Dusan Janjic.
The Serbian and Kosovo presidents both have a largely ceremonial role in domestic politics where executive powers reside in the hands of their prime ministers.
The two premiers, Serbia's Ivica Dacic and Kosovo's Hashim Thaci, have already met four times in Brussels since October, with Ashton as mediator.
Their next talks are slated for February 22.
The dialogue between the former foes has focused on easing daily headaches for people on both sides by easing border and customs' controls or mutually recognising each others' university diplomas.
But at stake for Serbia in the longterm are hopes of joining the EU, which is also dangling a carrot to Pristina of an accelerated path towards the bloc.
Shortly both sides will post so-called "liaison officers" in their respective capitals to boost communication, a key development.
But the most sensitive and complex issue is Belgrade's hope for some autonomy for the Serbs living in the tense north, as well as for 80,000 others in enclaves scattered throughout Kosovo.
Serb and Kosovo opposition leaders have strongly condemned the meeting.
In Pristina, they say it should be held only after Belgrade recognises Kosovo's independence, while in the Serbian capital, the meeting is seen in some quarters as another step by the authorities to "give up" Kosovo under international pressure.