Amid multiple investigations touching on Rudy Giuliani's work in Ukraine, one of his new lawyers, Robert Costello, said in an interview Thursday that the scope of representation is wide-ranging but that Giuliani is facing no real legal threats, just frivolous allegations.

False insinuations are "interfering with [Giuliani's] ability to represent the president of the U.S., and therefore it's interfering, in effect, with the 2020 election. Isn't that ironic?" said Costello of Davidoff Hutcher & Citron.

Costello is one of Giuliani's three new lawyers, along with Eric Creizman and Melissa Madrigal, two partners from Pierce Bainbridge Beck Price & Hecht, Giuliani tweeted this week. Any division of responsibility between Costello and the Pierce Bainbridge lawyers was still being discussed, Costello said.

Costello said the representation isn't cabined to one topic, such as the House of Representatives impeachment process, where Giuliani was subpoenaed, or a reported investigation by federal prosecutors in the Southern District of New York into whether Giuliani had broken the law in his interactions with Ukrainian officials.

"The scope is to assist him with whatever he wants us to assist him with," Costello said, adding that Giuliani first called him on Oct. 29 seeking representation.

Giuliani's lawyers are not conventional white-shoe counsel in investigations sprawling through Congress and the federal prosecutor's office.

While Davidoff Hutcher is well-known in New York and Costello has represented a host of high-profile celebrity defendants, the firm has no Washington, D.C., office. Pierce Bainbridge, meanwhile, is known for founder John Pierce's brazen ambitions to grow swiftly to become a top-tier plaintiffs' firm, but has recently seen some departures and is locked in litigation with an ex-partner making eyebrow-raising allegations.

Giuliani's selections are not completely surprising, however. Giuliani has a long friendship with Costello — they've known each other for some 48 years. Meanwhile, Pierce, a big fan of President Donald Trump, has been courting Giuliani for some time, with two sources telling Law.com that Pierce had even sought to have Giuliani join his firm as a partner.

Costello said his work was not being done as a courtesy, but that Giuliani was a fee-paying client. He declined to say whether Giuliani was a client of his firm's or only his own client. Sid Davidoff, the firm's senior partner, on Wednesday referred a call about the representation to Costello.

The news of Giuliani's turn to Costello and Pierce Bainbridge came after four other big firms decided not to move forward with Giuliani as a client, for one reason or another: Debevoise & Plimpton, Paul Weiss Rifkind Wharton & Garrison, Bracewell and Mayer Brown, according to a New York Times report.

In the interview with Law.com, Costello said he didn't know if that report was true, but said conflicts arise all the time, and may have with some of those firms.

Costello said also he will vigorously defend Giuliani, saying allegations being tossed around in the press are meritless.

"Every day brings a new, quite frankly frivolous, allegation about him. He's become a lightning rod for false allegations," said Costello, who briefly represented Michael Cohen in the Mueller investigation in a relationship that eventually turned sour.

"Some of them are just manifestly ridiculous, but that doesn't stop those people on the air, particularly cable TV stations, from running with it, because they like to run stories like, 'if Rudy Giuliani did this, that would be [bad]. … It's meaningless," he continued, emphasizing the hypothetical nature of such stories.

In a past interview with Law.com, Costello expressed frustration with what he saw as naivete by his former client Cohen. Costello has said Cohen saw TV personalities and journalists as his friends. Asked on Thursday whether Giuliani would continue to appear on TV to defend the president, Costello said, "That is up to Rudy, but my situation with Cohen was vastly different."

No one at Pierce Bainbridge was available for an interview on the topic by press time. John Pierce said in a short statement on Wednesday that his firm was "thrilled" to represent Giuliani.