Former presidential candidate and New York City Mayor Rudy Giuliani (R) has been offering “frank” advice and guidance to Donald Trump throughout February, the Washington Post reported.

“We’ve been talking. Donald and me, Donald and a few other friends who know politics. He calls to check things out or I’ll call him to say, ‘Donald, you’re going too far’ or ‘What you said was great’ or maybe ‘Change it a bit.’ It’s nothing formal. It’s kind of a running conversation,” Giuliani told the Washington Post in an interview published Sunday. “There is candor and there is trust.”

Giuliani has not endorsed a candidate in the Republican presidential primary and said he’s just consulted Trump “as a close personal friend.” And he’s not the only one. The former New York City mayor told the Post that several people he knows have been in touch with the Republican frontrunner.

“I could easily list off some names for you but that’s for Donald to say,” Giuliani told the Post.

He told the Post that his discussions with Trump have been “frank.”

“I think he could over perform in a general election similar to what Reagan did in 1980, bringing in new people,” Giuliani told the Post. “He has that ability. On the other hand, I’ve told him when I’ve disagreed, telling him when I think he may be hurting himself.”

Trump confirmed to the Post that Giuliani has called him with advice.

“Rudy is a very knowledgeable friend. I consider his counsel very important,” the Republican presidential candidate said in an email.

The former New York City mayor has defended Trump’s remarks in the past. In a July interview, Giuliani said that Trump’s comments that Mexican immigrants are “rapists” did not “reflect on Donald Trump as a man who is a very charitable and a good man.”

But Giuliani told the Post that he did not agree with Trump’s criticism of former President George W. Bush. During a February Republican presidential debate, Trump suggested that Bush did not keep the country safe on Sept. 11, 2001. Yet Giuliani praised Bush in his interview with the Post.

“I thank God that George W. Bush was president during 9/11,” Giuliani said.