David Dalgarno - regarded as one of the City's leading employment lawyers - will join employment guru Fraser Younson, who arrived at McDermotts from Baker & McKenzie in April.
Younson, head of employment at McDermotts, says: "I don't know of any other firm that has two eminent 'named' employment lawyers."
He adds that the employment practice has "a lot of business waiting to come across" as well as work from existing McDermotts clients with a UK presence.
The employment practice is a key element in the firm's strategy of building a full-service London office. "You have to have employment lawyers to provide services on corporate trans-actions like stock options and takeovers," says Younson.
Some doubt McDermotts' ability to match its ambitions, but Dalgarno says: "I am delighted with the commitment and resources that McDermotts is putting into establishing a leading full-service office in London."
Younson's move to McDermotts caused a major stir among employment lawyers, and the appointment of another leading player has been much anticipated.
Top employment practitioners see Dalgarno as a sensible acquisition for the newly-arrived US firm.
Fox Williams employment partner Jane Mann says: "The combination is going to be a significant force to be reckoned with in the employment law world."
Younson has also hired five assistants for his team. They are Alison Weatherfield from Warner Cranston, Oliver Dale from Edge Ellison, Angus MacGregor from Freshfields, Melanie Hunt from Eversheds and Charlotte Davies from Slaughter and May. One appointment is pending.
Victoria Parry, who is a senior associate at Warner Cranston, replaces Dalgado as head of the firm's employment group.