The move is likely to produce a fight between Olswang, Forsters and Eversheds for many of Freres' former media clients such as Warner Brothers, which has worked with lawyers going to all three firms.
Hermer acted for Warners on several deals, including its recent joint venture with ENIC.
Morgan's clients include Cox Communications, Two Way TV, Rea Brothers and Greig Middleton.
Olswang is hoping the pair will bring more Freres staff with them. “We hope they will be joined here by a number of their present team,” said head of corporate Adrian Bott.
He added: “Stephen and Simon are a perfect fit for us and the combination will bring reciprocal benefits for our practice and theirs. They are well known to many lawyers here and we have a number of clients and connections in common.”
With Hermer, Morgan, and Dibb Lupton Alsop's Tina Cowen, who joined on 1 May, the corporate department will have 13 partners.