Baugur's bid was first mooted at the start of May and was confirmed last week (26 May). It would be an unsolicited offer for House of Fraser, which is valued at just under £450m based on current share prices.
In April this year, Baugur bought a 10 per cent stake in House of Fraser as part of an ongoing assault on UK companies.
Slaughter and May is expected to secure the mandate for longstanding client House of Fraser. It advised the chain on the discussions with Apax and is House of Fraser's usual corporate law firm.
A&O maintained an exclusive relationship with Baugur until November 2003, when it lost the client to Stoke-on-Trent firm Heatons. Heatons acted for Baugur on a number of transactions before A&O clawed back a role on Baugur's bid for The Big Food Group in December 2004.
The firm also advised Baugur on its aborted offer for Somerfield in February 2005.
A&O declined to comment on the possible House of Fraser deal. Slaughters did not return calls for comment.