The spoof, which was recorded in 2000 when Mr Trump was a property magnate, transpired as part of the Mayor’s Inner Circle Press Roast. This was an annual event which sees New York politicians and White House journalists stage skits and parody themselves for charity.
The clip sees Mr Giuliani, who joined Mr Trump’s legal team last month to represent him through the Justice Department’s investigation into Russia meddling in the 2016 presidential election, dressed in drag flirting with the president.
The video culminates in Mr Trump nuzzling his face into Mr Giuliani's fake breasts.
"Oh, you dirty boy, you!" the mayor exclaims and slaps Mr Trump in the face.
"Donald, I thought you were a gentleman!" Mr Giuliani’s alter-ego says as he distances himself from the mogul-turned-politico.
"Can't say I didn't try!” Mr Trump replies.
The footage takes on a different meaning in light of the now infamous Access Hollywood 2005 tape which was leaked in 2016.
In the tape, Mr Trump could be heard bragging about groping and making unwanted advances on women and saying he was such a “star” that he could grab women “by the pussy”.
On Monday, the video of the world leader and Mr Giuliani became one of the top items in Reddit’s thread for gifs and videos. A version posted on YouTube since 2006 has racked up over two million views.
The video previously surfaced during the 2016 presidential campaign when late night TV host Stephen Colbert showed it on his show in the wake of an attack by Mr Giuliani, then a Trump campaigner, on Democrat presidential rival Hillary Clinton.
Since joining Mr Trump's legal team Mr Giuliani has made a series of notable television appearances.
This includes making the bombshell admission last week Mr Trump repaid his personal lawyer, Michael Cohen, for the $130,000 payment to adult actor Stormy Daniels as part of a nondisclosure agreement related to an affair Ms Daniels says she had with Trump in 2006.
But on Sunday Mr Giuliani was challenged over how his statement appeared to contradict Mr Trump’s earlier denial of knowledge of the payment to Ms Daniels.
Mr Giuliani responded by saying the talk of a $35,000 a month retainer was just “rumour” – despite him having said days earlier that it was fact.