Johnson, who has been in Australia for family reasons, is back in Wales and looking forward to getting back to work with the players.
"I'm back and its business as usual from here on in," said Johnson. "I can't wait to get back to talking about rugby and working hard with the squad and I am looking forward to establishing a strong working relationship with Mike."
Ruddock expects to make a further announcement next week with the position of defence coach still to be filled within the management set-up, but the agreements reached with Johnson and Hore come as a welcome boost.
"Scott and Andrew have done a great job and achieved a lot over the last two years and I will hopefully be able to bring some of my own experiences into the set up now and enhance the team's performance.
"We are also just a week or so away from appointing our defence coach who will be the final piece in the jigsaw and a key member of the team."