Jones Day and Simpson Thacher & Bartlett are among a clutch of firms to have landed prize mandates on Reynolds American's mammoth $27.4bn (£16bn) planned acquisition of rival Lorillard.

Tobacco giant Reynolds, which owns RJ Reynolds Tobacco Company, is known for its Camel and Pall Mall brands. The deal will combine these with Lorilland's Newport menthol cigarettes.

Reynolds has also reached a related agreement with Imperial Tobacco that will see the UK group buy Reynolds' cigarette brands KOOL, Salem and Winston, as well as Lorillard's Maverick brand and e-cigarette brand blu, for $7.1bn (£4.1bn) in cash.

The deal is expected to close in the first half of 2015.

Jones Day is advising Reynolds on the deal, with corporate partners Jere Thomson and Randi Lesnick leading the team.

Simpson Thacher & Bartlett is representing Lorillard on all aspects of the deal, fielding New York corporate partners Robert Spatt and Eric Swedenburg. Other corporate partners with roles on the transaction include London-based pair Adam Signy and Derek Baird.

Allen & Overy is acting for longstanding client Imperial Tobacco. The team, led by London corporate partner Jeremy Parr and New York corporate partner Eric Shube, includes New York antitrust partner Elaine Johnston. The firm worked closely with Imperial senior corporate and commercial counsel Anthony Pickard-Rose.

Kirkland & Ellis is advising Lazard, the lead financial adviser to Reynolds, with a team fronted by corporate partners Sarkis Jebejian and David Feirstein.

Both Centerview Partners and Barclays, which are the financial advisers to Lorillard, have turned to Sullivan & Cromwell for advice. The New York-based team includes corporate partners Francis Aquila and Brian Hamilton.

British American Tobacco (BAT) has agreed to invest around $4.7bn (£2.7bn) as part of Reynolds' acquisition, allowing it to retain 42% ownership in the company after the takeover. Lorillard's shareholders will meanwhile hold on to 15%.

Cravath Swaine & Moore is acting for BAT with a team led by corporate partners Philip Gelston and Ting Chen, who are supported by tax partner Michael Schler and antitrust partner Christine Varney.

Herbert Smith Freehills (HSF) is supporting Cravath in representing UK-listed BAT on the transaction. The team, which is advising on English law aspects, is led by corporate partners James Palmer and Gillian Fairfield, with support from finance partner Will Nevin. HSF is also working for BAT on the financing of the deal.

Cravath's Gelston, Chen and Schler were recently mandated on Swiss chocolate company Lindt's acquisition of US confectionary rival Russell Stover.