In September Pagni said he wanted a range of firms, both in the magic circle and beyond (The Lawyer, 3 September). Since then around 20 firms have approached Alliance Boots about panel places.
It is understood that A&O will lead antitrust advice, while the company will turn to Bakers for pensions advice.
Slaughters advised Alliance Boots on its £11.2bn management buyout, backed by Kohlberg Kravis Roberts (KKR), which completed earlier this year. The high street giant became the first FTSE100 company to be taken private.
It was during the buyout that Pagni got to know Clifford Chance, which advised KKR.
The buyout had postponed Pagni's original plan for a panel review after Alliance Unichem and Boots merged in an £8.1bn union in summer 2006. A&O and Slaughters advised the respective legacy companies.