South Wales East AM Delyth Jewell will speak at a Welsh independence rally on Saturday, September 7.
The Plaid Cymru AM, who is a supporter of Welsh independence, will be joined by former Wales international goalkeeper Neville Southall and sports commentator Eddie Butler, among others.
The rally, which will be held in Merthyr Tydfil, is being organised by All Under One Banner Cymru (AUOB Cymru).
Ms Jewell AM said: “The rally on September 7 in Merthyr will be a truly historic day. Rallies have been held in Cardiff and Caernarfon and I’m so pleased that this rally will take place in the valleys, to show that this movement for change belongs to every corner of Wales.
“Merthyr has played its part in shaping the history of our nation – it’s fitting that she should be a central location in this exciting call for us to determine our own future.
“Whether people have been supporters of independence for years or have only recently become curious about the idea, I’d urge them to join the march on September 7. It’s going to be a really exciting, colourful day, and a celebration of everything our nation is and can be. Why not come and be a part of it?”