Mr Lambeth came on board at Kemp & Strang in September 2013 from Ashurst, which he joined in late 2010.
Prior to that, he spent ten years at Gilbert + Tobin in their Sydney office.
Mr Lambeth specialises in mergers and acquisitions, equity capital markets, company law and governance, according to a statement from Thomson Geer.
He has extensive experience advising in relation to takeovers, schemes of arrangement, Takeover Panel proceedings, board spills, IPOs, equity and debt issues, capital management transactions, corporate reconstructions and general Corporations Act advice.
Thomson Geer chief executive partner Adrian Tembel said the appointment would strengthen the firm’s M&A/ECM team.
Kemp & Strang have expanded rapidly in the past year, launching their second office in Melbourne in mid-2014.
The firm subsequently opened a Brisbane office in November last year, headed by partners from Thynne & Macartney.