Italy's President Sergio Mattarella has accepted a political novice as prime minister, paving the way for two populist parties to form a government.
The anti-establishment Five Star Movement and right-wing League chose law professor Giuseppe Conte in a bid to end 11 weeks of political deadlock.
The 53-year-old has faced claims that he embellished his CV, which he denies.
Concerns remain over the two parties, which reject years of EU austerity and want to renegotiate Italy's debt.
Speaking after emerging from talks with the president, Mr Conte said: "Outside of this palace there's a country that rightfully awaits a new government and answers. What is about to be born is the government of change."
He added that he would be the "defender of all Italians on the international and European stage".
Italy has been without a government since elections on 4 March, because no political group could form a majority.
Two populist party leaders, Luigi di Maio of the Five Star Movement and Matteo Salvini of the League, finally agreed a coalition deal after days of talks and later nominated Mr Conte as their candidate to be prime minister.
The coalition deal promises tax cuts, a guaranteed basic income for the poor and deportations of 500,000 migrants - policies that are likely to put the eurozone's third biggest economy on a collision course with Brussels.
Mr Conte will now form a list of ministers to be approved by the president before a new government can be sworn in. The cabinet will then face a vote of confidence in parliament.
Who is Giuseppe Conte?
Fifty-three-year-old Mr Conte, a professor of private law in Florence and Rome, is not an elected MP and until now has been completely unknown in politics. Since his nomination, he has been accused of inflating his academic resume in an effort to boost his international profile.
On a CV dating back to 2013, he said he had "perfected his legal studies" at New York University, but a spokeswoman for the institution said there was no record of him having studied there.
The resume also said he had carried out "scientific research" at Cambridge University's Girton College in 2001 - a spokeswoman for the university said it could not confirm or deny his claim citing data protection laws.
Mr Conte also said he had worked on his legal studies at the International Kultur Institut in Vienna, Austria. The school - which was misspelt on the CV - is in fact a language school and does not appear to offer legal courses.
The Five Star Movement defended its nominee on Tuesday, saying that Mr Conte had never claimed to have earned degrees abroad, but "went abroad to study, to deepen his knowledge, to perfect his English legal language skills".
It added: "The defamatory campaign is so explicit and crude that it will only strengthen us."
The Five Star Movement and The League named Mr Conte for the role of prime minister on Monday. Instead of immediately accepting the nomination, Mr Mattarella took some time to decide, as concerns rose in Italy over Mr Conte's lack of experience and questions over his CV.
He has also faced controversy over unpaid taxes and fines of over €50,000 (£44,000, $51,000).
With the president's green light it is now up for the parliament to decide on the coalition. The two parties have sufficient votes in the Chamber of Deputies, but only a small majority in the upper house, the Senate.
What do the parties want?
Italy was ravaged by the 2008 financial crisis that left the economy some 6% smaller and three million more people in poverty.
The policies promised by the parties are estimated to cost at least €100bn ($117bn; £88bn), experts say, for a country with the biggest public debt in the EU after Greece.
Other proposals include:
- Poor families will get a €780 basic monthly income, provided recipients actively seek work
- Two "flat tax" rates set at 15% and 20%, and families would receive a €3,000 annual tax deduction based on household income
- Scrapping sales and excise tax increases next year, worth €12.5bn
Neither Five Star nor The League are fans of the single currency, the euro. League leader Matteo Salvini said not long ago that the euro was "a mistake" for Italy's economy, while Five Star had wanted a referendum on Italy's future membership.
But they have dropped their initial ambition of exit from the euro and now talk of trying to reform it from within.