Billionaire activist-investor Carl Icahn gives an interview on FOX Business Network's Neil Cavuto show in New York February 11, 2014. REUTERS/Brendan McDermid

(Reuters) - Billionaire activist Carl Icahn, who has been making headlines with his epic battle with Apple Inc., might have another one on his hands - this time with his banker friends.

In an interview with FOX Business Network on Tuesday, Icahn called for the reinstatement of the Glass-Steagall Act, which separated investment banks and commercial banks.

Icahn declined to comment on JPMorgan Chase Chief Executive Officer Jamie Dimon being awarded a $20 million package, but said: "I am good friends with a lot of bankers (and they) may hate me for this, but I think the Volcker Rule is fine."

"I think what they should do is go back to Glass-Steagall," he told FOX Business. "A lot of my friends at these investment banks are going to be real mad at me for saying it, but I really think that was one of the problems in '08."

Icahn, who rarely comments on the nation's banks, was referring to the Depression-era law, which was repealed in the late 1990s.

Of course, Icahn had kind words to say about Apple.

In a letter to Apple shareholders on Monday, Icahn wrote he was ditching his non-binding proposal to force Apple to add another $50 billion to its stock buyback plan, "especially when the company is already so close to fulfilling our requested repurchase target."

Icahn told FOX: "I'm not going anywhere. I'm not leaving. I haven't sold one share, nor do I intend to. I think Apple is one of the cheapest stocks around and I've said that - Tim Cook and I agree on that. It's very undervalued."

(Reporting By Jennifer Ablan; Editing by Ken Wills)