Ross County have secured goalkeeper Daniel Bachmann on loan from Stoke City and agreed a fee with Celtic for midfielder Jackson Irvine.
Irvine, 22, has signed a two-year contract after spending last season on loan in Dingwall from the Glasgow club.
Austria Under-21 cap Bachmann will spend six months away from his English Premier League club.
He said: "It has all come out of the blue, but I am really looking forward to experiencing the Premiership."
Bachmann, who made 15 appearances on loan to Wrexham in the Conference last season, played in County's 2-0 friendly defeat by Nijmegen on Saturday.
Now the 21-year-old will compete with another former Celtic trainee, Scott Fox, their summer signing from Partick Thistle, for a first-team start.
Australia Under-23 international Irvine, who was out of contract with Celtic, returns to County after the two clubs agreed a development fee.
He had joined the Scottish champions from Melbourne outfit Frankston Pines in 2012, but he only made one substitute appearance for the Glasgow club and was sent out on loan to Kilmarnock and then County.
Irvine, who made 30 appearances for County last season, told County's website: "I'm delighted to be back at Ross County.
"I always knew it might be a possibility to come back and join the club permanently and now it's all agreed I couldn't be happier."