At least one prominent alternative investments firm plans to participate in the government’s toxic assets plan. WL Ross & Co. and its parent, Invesco, are planning to invest up to $1 billion in the Public-Private Investment Program unveiled a month ago by U.S. Treasury Secretary Timothy Geithner.

Invesco and its private equity affiliate will team with real-estate developer the LeFrak Organization and two mortgage firms to invest in PPIP, using existing capital. In addition to LeFrak, Assured Guaranty, American Home Mortgage Servicing, WL Ross and Invesco’s 120-strong fixed-income team, the group also includes a trio of securities, investment banking and advisory firms: Muriel Siebert and Co., Williams Capital Group and Atlanta Life Financial Group’s Jackson Securities.

Invesco’s participation in PPIP is big boost to the government program, which has received precious little support from the alternatives community. The world’s largest hedge fund, Bridgewater Associates, briefly flirted with PPIP, before sending a letter to its investors blasting the program.

But Invesco CEO Martin Flanagan doesn’t have any reservations.

“We strongly believe that the Public-Private Investment Program will help stimulate the mortgage market and provide individual and institutional investors globally with compelling investment opportunities in the Legacy Securities and Legacy Loan programs,” he said.