Visitors from the African city of Timbuktu will meet First Minister Rhodri Morgan while on a fact-finding trip to Wales.
Members of the delegation from Timbuktu have visited local schools
The delegation's week-long visit consolidates links with Hay-on-Wye in Powys after they chose the book town as their twin six months ago.
Last year there was an appeal in a national newspaper to find the city an international community partner.
The official twinning ceremony will take place in Hay-on-Wye on Thursday.
Welcoming the delegation from Timbuktu, Rhodri Morgan said the twinning was "yet another proof that Wales has not become inward looking and self-obsessed since devolution started in 1999".
Mr Morgan added: "Welsh people are renowned for their internationalist outlook and their desire to help those elsewhere in the world less fortunate than us living in Wales and this new, international partnership is a great example of what we are trying to achieve through the Wales for Africa framework."
Sue Newall, chair of the Hay2Timbuktu delegation committee, who is set up to oversee the twinning initiative said everyone involved was very "excited" about the project.
"The main event will take place on Thursday at 1830, when crowds will gather to witness the signing of the twinning document in the market square.
"Local schoolchildren have been busy rehearsing the Malian and Welsh national anthems, which they will sing as the two mayors sign the twinning document to officially seal the relationship," she added.
The town fought off 52 other challengers in February and Anne Brichto, driving force behind the twinning, describes it as "a modern partnership between two ancient cultures".
"It's been a long, exciting and magical journey," she added.
During its stay, the team from west Africa will promote links between schools and help people learn more about Mali and Timbuktu, which is on the southern tip of the Sahara.
It is hoped the initial visit will allow for exploratory discussions about future projects in the areas of education, health, art and music.
Delegates, including the mayor of Timbuktu, Said Ould Mahmoud, have already visited Hay- on-Wye Primary School and Gwernyfed High School in Brecon.
They also attended a reception at Westminster with Roger Williams, MP for Brecon and Radnorshire, on Monday.
On Wednesday, they will visit the Welsh assembly in Cardiff and meet Mr Morgan and Education Minister Jane Hutt before travelling to the Big Pit in Blaenavon.
Timbuktu - also spelt as Tombouctou - is already twinned with a Chemnitz in Germany, Saintes in France, Marrakech in Morocco, Kairouan in Tunisia, and Tempe in the US.
A return visit to Timbuktu is planned for spring 2008.