will fight pound-for-pound star Terence Crawford on April 20 after signing contracts on Friday.
reported on Thursday that a deal was imminent
and a formal announcement of Khan's challenge for Crawford's WBO welterweight title will be made in London
on Tuesday. It is expected that the fight will be in New York.
Khan will attend a press conference in the capital before immediately flying out to the US to start a training camp.
The fight will net the 32-year-old in the region of £4millon - less than he would have received for facing his long-time British rival Kell Brook.
By launching this ambitious assault on Crawford, he is going up against one of the leading fighters in the world at any weight, with the American's record standing at 34 wins from 34 fights with 25 knockouts and world titles at lightweight and light-welterweight, in which he held all four major belts.
Khan, who last held a world title in 2012, will fight in the US for the first time since his knockout loss against Canelo Alvarez in May 2016.