Anderson is set to join Lansons' nine-strong management board later this spring following 14 years at Fishburn, where she was made client services director in January.
Referencing her work with clients including Novartis, Tetra Pak and Tesco Bank, Lansons CEO Tony Langham said: "We really hit it off with Clare and see things in similar ways. We are great admirers of the culture of Fishburn in the early days. Her skills in financial services are attractive to us, and her broader corporate experience fits our diversification strategy."
He added: "Clare is the first of three senior hires we hope to make in the first half of the year. Our recent growth is in the corporate space, particularly from providing cross-disciplinary senior counsel – and from diversifying outside financial services."
Fishburn CEO Ali Gee said: "Clare has made a huge contribution to the business over the past 14 years and leaves with our thanks and best wishes for the future.
"We’re at an advanced stage on a number of key hires at the moment including significant senior appointments and hope to announce some news in the coming weeks."
Last week PRWeek revealed that Alastair Fairbrother was joining Allianz Global Investors from Fishburn, which was rebranded from Fishburn Hedges amid a wider restructure announced in November.