The director of Switzerland's Federalism Institute, Thomas Fleiner, is to advise the Serbian government's team negotiating the future status of Kosovo.
The announcement came as a special envoy to United Nations Secretary-General Kofi Annan opened talks on how the Balkan province should be governed in future.
Negotiations formally started on Monday when the former Finnish president, Martti Ahtisaari, arrived in Kosovo.
The province has been under UN and Nato administration since a 78-day Nato-led air war halted a Serb crackdown on ethnic Albanians in 1999.
Tensions remain high, with local ethnic Albanians demanding independence, a move rejected by the Serbian government in Belgrade.
Fleiner, a lawyer who has headed the Fribourg-based Federalism Institute since 1984, told swissinfo Serbia and Montenegro had approached him because of his knowledge of "federalist systems, multiculturalism and international law".
He said his role would mainly be that of legal adviser to Belgrade's negotiating team.
"I will also be able to give advice and ideas on what solutions [for Kosovo] could be considered by looking at examples we have in the world of autonomy and multiculturalism," he added, pointing to Switzerland's own federalist structure as "one possible model among many others".
Fleiner expects to shuttle between Switzerland and Belgrade on a "fairly regular" basis over the next few months as status talks get underway.
But he said he would not be taking an active role in the political horse-trading.
"I am certainly not someone who has been asked to have a political impact on these negotiations."
The Serbian negotiating team will be led by Prime Minister Vojislav Kostunica and President Boris Tadic, who earlier this year criticised the Swiss government for making a public statement in favour of a form of independence in Kosovo.
Belgrade has called on Switzerland not to jeopardise its credentials as a neutral facilitator.
Fleiner would not be drawn on whether the Swiss had made a mistake by publicly endorsing the idea of an independent province even before the start of status talks.
But he made it clear that continuing with the status quo was not an option.
"The UN peacekeeping force [in Kosovo] was only ever meant to be a solution for a limited time, so we have to find something more sustainable," he said.
The federalism expert is quick to play down suggestions that there might be a "quick fix" for Kosovo, saying that nobody should believe "you can solve such a historically long-lasting problem in [just] a couple of weeks".
"It's not unusual that you have totally opposite positions at the beginning of negotiations.
"Now it is up to the mediators to explore where they can find [room for manoeuvre]... and which positions they cannot give up because they would be considered traitors by their own people."
swissinfo, Ramsey Zarifeh