Ireland and Afghanistan were awarded Test match status on Thursday, taking the number of countries playing at the pinnacle of cricket from 10 to 12 in a decision described as "fantastic" and "remarkable".
Both countries were confirmed as full members after a unanimous vote at an International Cricket Council (ICC) meeting during its annual conference in London.
Now the Ireland and Afghanistan's men's teams will be eligible to play five-day Test cricket, widely regarded as the sport's supreme format.
Bangladesh were previously the last country to be granted Test status in 2000.
Afghanistan and Ireland have joined an exclusive club that also includes founder members Australia and England, who played the first Test match at Melbourne in 1877, South Africa, New Zealand, the West Indies, India, Pakistan, Sri Lanka and Zimbabwe.
"It's fantastic news for all involved with Irish cricket and I'd like to thank the ICC and the members for the positive outcome," said Cricket Ireland chief executive Warren Deutrom in a statement.
"Test cricket is the pinnacle of the sport and it's what we've all been aiming for."
Ireland captain William Porterfield emphasised the point.
"We have all played in World Cups and achieved some memorable results along the way, but to play in a Test would be a bit special," he said.
Meanwhile Afghanistan Cricket Board chief executive Shafiq Stanikzai said: "For a nation like Afghanistan it is a huge and remarkable achievement, the entire nation will be celebrating.
"Afghanistan cricket has gone from strength to strength and we dared to dream that this would happen and today it has become a reality."
Afghanistan international Mohammad Nabi took to Twitter to label the elevation a dream come true.
Finally our hard work pays off and the dream of @ICC Full-Membership comes true. Can't control my sentiments . الحمدلله— Mohammad Nabi (@MohammadNabi007) June 22, 2017
Stanikzai said in a subsequent conference call with reporters that he would "consult with the "Full (Test) members in our region," regarding the staging of Afghanistan's first Test.
The team have recently played home matches in the Indian city of Noida because of security concerns.
Many Afghans' first contact with cricket only took place during the 1980s and 1990s, as refugees fled to Pakistan to escape the Soviet invasion.
By contrast, cricket has been played in Ireland for nearly 200 years.
But it wasn't until 1969 that Ireland made the rest of the world game sit up when they bowled out the West Indies for just 25 at Sion Mills.
Ireland have since established themselves during the course of several World Cups, recording one-day international wins over Pakistan, the West Indies and England.
Now the Taoiseach, or Prime Minister, of the southern Republic of Ireland, Leo Varadkar, wants to see that success carried on into the Test arena.
"We can now look forward to some great days ahead as Ireland takes on the top Test cricket playing nations in the world," Varadkar said.
Cricket Ireland chairman Ross McCollum added he would hold talks with "several parties" about Ireland's inaugural Test and a home fixture in the format in 2018.
The ICC announced the establishment of cricket's newest Test nations with a Twitter statement saying: "@ACBofficials and @Irelandcricket confirmed as Full Members after a unanimous vote at ICC Full Council meeting.
"Both will now be eligible to play Test cricket."
ICC chief executive David Richardson added: "I'd like to congratulate Afghanistan and Ireland on their Full Membership status which is the result of their dedication to improving performance both off and on the field resulting in the significant development and growth of cricket in their respective countries.
"Both have clearly demonstrated they meet the new criteria and as such have made the progression to Full Membership," the former South Africa wicket-keeper said.
Questions remain, however, about how well Afghanistan and Ireland will do in the game's longest format.
Bangladesh famously floundered for their first decade while New Zealand took 26 years to win their first Test.