Freshfields Bruckhaus Deringer has won a role alongside Gibson Dunn & Crutcher on Hewlett-Packard's $1.5bn (£972m) acquisition of security software maker ArcSight, reports The Am Law Daily.

Russell Hansen, the partner-in-charge of Gibson Dunn's Palo Alto office, is leading the US firm's team on the deal, while Freshfields partner Alan Ryan and senior associate Martin McElwee are serving as European antitrust counsel.

Hansen also advised HP on its $1.2bn (£780m) acquisition of handheld device maker Palm earlier this year.

Gibson Dunn is also currently advising HP on a civil suit filed last week against former CEO Mark Hurd over his move to tech company Oracle.

US firm Drinker Biddle & Reath has also won a role on the deal to provide US antitrust advice to HP, while HP deputy general counsel Paul Porrini headed the in-house legal team. HP general counsel Michael Holston was a partner at Drinker Biddle from 1987 to 2005.

US firm Fenwick & West is advising ArcSight, which provides network security consulting and compliance management services to corporate clients. The firm also represented ArcSight on its initial public offering in early 2008. ArcSight general counsel Tram Phi is a former Fenwick associate.

The deal, which is expected to close by the end of the year, comes two weeks after HP beat out Dell to acquire data storage company 3PAR.

The Am Law Daily is a blog on law.com, Legal Week's US affiliate title.