The fund, run by Norges Bank Investment Management (NBIM), took a 25 percent stake in the Quadrant 3 scheme, a £390m redevelopment of an art-deco hotel, with surrounding buildings, at the south end of Regent Street.
David Shaw, Head of the Regent Street Portfolio said: "The Quadrant 3 investment deal with NBIM is the twelfth and largest investment and development deal executed by the Regent Street Partnership since its formation some 30 months ago.
"We are extremely happy to be partnering with NBIM on our award winning Quadrant 3 investment and look forward to further growing this successful relationship in the future."
The fund aims to increase the share of property investments in its portfolio from some 0.9 percent of its value today, closer to its maximum allowed threshold of 5 per cent.
Last month it paid $684m for a 45 per cent stake in New York's Times Square Tower.