The engineering company also reappointed existing panel member Eversheds alongside Addleshaws to act on national issues. Freshfields Bruckhaus Deringer, Rolls-Royce's main legal adviser on litigation and corporate, was unaffected by the tender.
The two national firms took spots on the panel after a beauty parade, in which Pinsent Masons and Wragge & Co pitched.
The Addleshaws team was led by corporate partner Michael Birchall, who will act as the relationship partner for Rolls-Royce.
On the tender Birchall said: "We're looking forward to building a strong relationship where the emphasis will be on supporting the ambitions and priorities of the Rolls-Royce legal team as well as the wider Rolls-Royce business."
Birchall's involvement in the pitch was advantageous to Addleshaws as he advises United Utilities and has a close relationship with the utility company's former general counsel Tim Rayner, who joined Rolls-Royce last April.
Eversheds also had links with United Utilities while Rayner was in-house chief, although corporate partner Stephen Kitts has had a strong relationship with Rolls-Royce for almost a decade.
Kitts added: "Not only do we act for Rolls-Royce in the UK, but we've also acted for the company in continental Europe and Scandinavia and we look forward to continuing to build on our longstanding relationship with them."