Ireland and Afghanistan have been granted Test status by the International Cricket Council.
It increases the number of countries competing at the top level of international cricket to 12.
They are the first admissions since Bangladesh gained Test status in 2000.
The two countries, who already have one-day and Twenty20 international status, have enjoyed notable successes against Test-playing nations in global competitions in recent years.
Ireland, who are 12th in the ICC one-day rankings, beat England in the 2011 World Cup, four years after a shock victory over Pakistan in the same competition.
Afghanistan, currently 10th in the rankings, drew an ODI series with T20 world champions West Indies this month.
The changes were passed unanimously at the ICC full council meeting at The Oval.
Ireland captain William Porterfield says it will be a "special day" if he leads his side out for their first Test.
Wicketkeeper Gary Wilson described it as a "historic day", writing on Twitter: "Years worth of work feels like it has been recognised. Here's to the beginning."
Cricket Ireland chairman Ross McCollum said: "We will start discussions with several parties about staging our first Test.
"We are sincerely grateful to the ICC and its members for giving us this honour.
"It is a recognition of the quality of our teams over the years, male and female, of our talented administration, and of the strength of our domestic and club structures."
|When each nation became a full member, thus gaining Test status|
|England (founder member)||1909|
|Australia (founder member)||1909|
|South Africa (founder member)||1909|
'The entire nation will be celebrating'
Afghanistan's rise has been rapid - the cricket board was only formed in 1995, by Afghan refugees living in Pakistan, but the country gained full ODI status in 2011 and became an ICC associate member in 2013.
They beat West Indies in reaching the Super 10 stage of the World Twenty20 last year.
Afghanistan beat Ireland by an innings and 172 runs in a four-day Intercontinental Cup in March in April.
Leg-spinner Rashid Khan and off-spinner Mohammad Nabi both impressed in the recent Indian Premier League; Khan was the sixth highest wicket-taker in his debut campaign with 17 scalps.
Both broke into the top 10 of the ODI bowling rankings during the recent tour of the West Indies, when Khan took 7-18, the fourth best ODI bowling figures in history.
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 across all five regions and different provinces - it is the perfect Eid gift."