NEW YORK CITY-The long search is now over. Following a six-month selection process, a partnership of Lehman Brothers Holdings and L&L Holding Co., the master leaseholder of 425 Park Ave., has selected Foster + Partners to redesign the office building into a state-of-the-art skyscraper, the companies unveiled in a joint statement Wednesday morning. Upon completion, it will be the first new office tower on Park Avenue in more than 50 years.

Known for their work on the Hearst Tower in Midtown and the World Trade Center site in Lower Manhattan, Foster + Partners, a London-based architecture firm, will partner with Rogers, Stirk, Harbour + Partners (Lord Richard Rogers), OMA (Rem Koolhaas) and Zaha Hadid Architects to participate in the final conceptual design phase of the competition over the summer.

Later this month, L&L chairman and CEO David Levinson and Lord Foster will make a presentation on the conceptual design during the Municipal Art Society’s third annual “Summit For New York City” on Oct. 19. The two-day summit, which begins on Oct. 18, will also feature an exhibit featuring the 425 Park Avenue design concepts that were presented by each of the four finalists in the competition. In total, 11 firms participated in the challenge.