President-elect Donald Trump is to make son-in-law Jared Kushner one of his senior advisers.
The 35-year-old played a key role in the presidential campaign and his new White House job will cover both domestic and foreign policy.
Mr Kushner, who is married to Ivanka Trump, is a property developer with a wide range of business interests.
His appointment will be controversial because of nepotism laws and concerns over potential conflicts.
The news was confirmed by Trump spokeswoman Kellyanne Conway, who described it as the “best news of the day”.
Members of Mr Trump’s team have argued that a law barring officials from giving government jobs to relatives does not apply to White House positions.
There are also federal ethics laws that mean government employees cannot profit from any businesses.
Mr Kushner’s lawyer has said he would step down as boss of his family’s real estate business if he took a White House job, and extricate himself from some of his assets.
Jamie Gorelick of law firm WilmerHale said Mr Kushner was committed to complying with federal ethics laws and had consulted with the Office of Government Ethics about what steps to take.
Mr Kushner was often seen by his father-in-law’s side during the presidential campaign and was heavily involved in its digital strategy.
He was said to have played a role in the ousting of New Jersey Governor Chris Christie from the transition team during the campaign.
While US attorney for New Jersey, Mr Christie prosecuted Mr Kushner’s father for tax evasion and witness tampering, and he served a jail sentence.
Mr Kushner has also been present at Cabinet interviews and in key meetings with foreign leaders.
He owns 666 Fifth Avenue, a skyscraper a few blocks down from Trump Tower, and aged 25, he bought the New York Observer newspaper.
Several of Mr Trump’s Cabinet picks have business interests that will be scrutinised at confirmation hearings taking place this week.