The much atticipated fight is expected to be announced officially on Monday.
The bout had been called off earlier this week with the two camps unable to agree financial terms.
Williams said: “Richard Scharfer assures me he has a signed contract from Manny Pacquiao, which is fantastic.
“I am 99 per cent certain the fight will take place and that Ricky Hatton now has this fight to look forward to.
“I spoke to Jeng Gacal (Pacquiao’s lawyer in the Philipinnes) on Thursday and I hope that has helped to push the fight through.”
Richard Schaefer, CEO of Golden Boy Promotions, Hatton’s promotional agent in the United States, said: “I don’t anticipate there being any problems and I’m hoping by Monday to officially announce the fight.
“Judging by the anticipation of the announcement, it should be one of the biggest fights in years.”
It is believed both fighters are to receive $12 million and a share of pay-per-view television revenue.
