Queens Park Rangers manager
Hughes worked with former England frontman Johnson, 31, during their time at Fulham, while Nelson will sign on at Loftus Road after the end of his contract at Tottenham Hotspur.
Johnson feels he is joining QPR at an exciting time, the west London club having secured another season in the top flight on the final day despite a last-gasp defeat at champion Manchester City.
"I have worked closely with Mark before and there are also players here that I have played with previously, including
"Those were factors in me joining, but this is a big, big club.
"I have spoken to the chairman and Mark, who both have great ambition for QPR, and it is something that I wanted to be a part of.
"Mark told me about the plans for a new training ground and how the club wants to go forward. That really excited me."
New Zealand defender Nelson, 34, joined Spurs in January after seven years at Blackburn Rovers where he played under Hughes.
Nelson has penned a one-year deal with QPR and admitted reuniting with his old boss was a 'massive draw'.
He said: "I like his winning attitude. He and all his staff just have an absolute desire to win, and that's what the Premier League is all about.
"If you haven't got that, you won't be successful.
"The owners have got fantastic ambition and it's exciting to become a part of that.
"There is a real buzz about the place and it is a privilege to be here."
Hughes expects Nelsen, who is set to play for his country at the Olympic Games, will add some much-needed Premier League experience to the QPR team.
"I know what he is all about and what he can offer us, both on and off the pitch," said Hughes, who took charge at Loftus Road in January, replacing Neil Warnock.
"He is a fantastic professional with a great work ethic and it will benefit the younger lads in the group to see how he goes about his work.
"Ryan has got great experience in the Premier League and that is something our squad is lacking a little bit at present."
QPR will kick off the new campaign at home to Swansea City on the opening day.
Assistant manager Mark Bowen accepts it will be form away from Loftus Road which will be key to avoiding another relegation scrap.
Bowen said: "We know what we and the fans can produce at home, but we need to replicate that away.
"If we want to push on as a club we need to address it as soon as possible."
After a trip to Norwich City, QPR plays champion Manchester City, hosts Chelsea and then is at Tottenham Hotspur.
Bowen added: "We will need to get some points on the board from those first two games, because the next three are very tough on paper - but that is the Premier League in a nut-shell.
"There are no easy games at all in this division, which is why it is one of the best in the world."
English Premier League
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