Kushner would be an “invaluable member of my team as I set and execute an ambitious agenda,” said the President-elect in a statement acknowledging the appointment, Efe news reported on Tuesday.

According to the statement released on Monday, Kushner would work closely with Chief of Staff Reince Priebus and White House chief strategist Stephen Bannon, forming a trio.

Trump said that this trio would be an effective leadership team.

The communique also emphasised the role that Kushner had in the election campaign that culminated in Trump’s November 8 win, saying that his participation was “instrumental” in formulating and executing the winning campaign strategy.

Kushner, an Orthodox Jewish real estate businessman, who is married to Ivanka Trump, the mogul’s older daughter, would forego his salary as presidential advisor, the communique added.

The possibility that Trump’s son-in-law would join his team was discussed for several weeks, although that would appear to pose personal challenges for Kushner because he would have to divest himself from his business activities to take on a government post.

Kushner, who would turn 36 on Tuesday, is the CEO of a company focusing on New York and New Jersey real estate investments and since 2007 he has closed deals worth some $13 billion, according to data from the firm.