McGhee - double swoop.
Motherwell have signed midfielder Jim O'Brien from Celtic on a permanent basis.
The Fir Park club have also brought in Blackburn goalkeeper Gunnar Nielsen on loan for six months to compete for a place with Graeme Smith.
O'Brien, 20, admitted it was a relief to complete his move to Motherwell, where he had been on trial since last month.
"I am just delighted to be here," he told official website www.motherwellfc.co.uk after clinching a two-year contract.
"The important thing for me just now is to play regular first-team football."
O'Brien had loan spells with Dunfermline and Dundee United in the past two seasons, having failed to make a significant impact at Celtic who accepted an undisclosed fee for his services.
He will have European football to look forward to, after Mark McGhee's side 'Well secured a surprise UEFA Cup place by finishing third in the SPL last season.
"Obviously working under a manager like Mark McGhee is a big pull and all the guys have made me feel really welcome," said O'Brien.
"First-team football is what it is all about for me now. I've signed for two years and I want to establish myself in the team and make a name for myself and repay the club for having faith in me."
He added: "The pull of UEFA Cup football has been a big one and that is another level I am keen to experience."
Nielsen, 21, joined Blackburn last summer and new Rovers boss Paul Ince will hope the Faroe Islands Under-21 international gains worthwhile experience from his spell in Scotland.
He said "I've come here for six months and I will do my best to push Graeme for the first-team shirt.
"Hopefully I will get into the team and my aim is to improve myself as a player and help the club as much as I can."