The funeral of Rhodri Morgan will be held at the National Assembly today
The 77-year-old spent more than 30 years in politics and led the country as first minister for almost 10 years from 2000.
Following his death on May 17, General Election campaigning was suspended by all parties in Wales and tributes poured in from across the political spectrum.
Jeremy Corbyn described him as a giant of the Labour movement, while Welsh Secretary, Conservative Alun Cairns said Mr Morgan was a "great servant to Wales".
The ceremony, which will be open to the public, will be held at the Senedd in Cardiff Bay from 11am and will be conducted by humanist celebrant and former assembly member Lorraine Barrett.
It will be relayed through speakers on the steps of the Senedd and streamed live on www.senedd.tv.
The former Welsh first minister spent more than 30 years in politics
He was an extraordinarily clever man, but loved his sport, loved to talk to people
Mr Morgan was elected as MP for Cardiff West in 1987, working as shadow environment spokesman and chairing the House of Commons public administration select committee before assuming office in the Assembly in 1999.
He did not see eye-to-eye with former prime minister Tony Blair, who overlooked him to lead the Welsh Assembly in 1999, and moved to distance himself from New Labour.
General Election campaigning was suspended by all parties in Wales following his death
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But he took on the role in 2000 following the resignation of Alun Michael, now police and crime commissioner for South Wales.
In September 2009, on his 70th birthday, Mr Morgan announced he would be relinquishing his post as first minister, with Bridgend AM Carwyn Jones succeeding him.
Around 12 months later, Mr Morgan announced he would be retiring from politics altogether.
Mr Morgan's wife Julie is assembly member for Cardiff North.
Paying tribute, Mr Jones said he was "very shocked, desperately sad", adding that his thoughts were with Mrs Morgan and the family.
Jeremy Corbyn described him as a giant of the Labour movement
"He was an extraordinarily clever man, but loved his sport, loved to talk to people," Mr Jones said.
"He was encyclopaedic about sport, he could go back decades. He had an eerie talent for remembering people's names.
"One you had met Rhodri, he would remember your name. That was an incredible talent that he had."
Following the funeral ceremony at the Senedd there will be a service of committal at the Wenallt chapel, Thornhill Crematorium the following day on Thursday at 2pm, which will also be open to the public.
People wishing to attend the funeral ceremony at the Senedd, which will open at 9.30am, are advised to arrive early to allow for security checks to be carried out.