In the sketch, Sessions unpacked his desk and reminisced about his short time as head of the Justice Department. He was also disappointed that President Donald Trump did not visit himself to say goodbye.
However, Mueller, who in the real world is investigating Russia's influence on the 2016 presidential election and the Trump campaign's alleged involvement, did show up to tell Sessions that he helped in more ways than he will ever know.
"You know in Harry Potter when an elf gets a piece of clothing, it sets him free?" Mueller asked Sessions. "This is for you."
Mueller then gave Sessions a piece of toilet paper from the bottom of Trump's shoe, which Sessions then put in his pocket.
"You're a weird little dude, Jeff," Mueller said.
Sessions warned Mueller not to get cocky, reminding him that Acting Attorney General Matthew Whitaker might remove him. Sessions then transitioned to singing the rest of Adele's "Someone Like You." Mueller even joined in.
"Don't you worry, I'm still going to be a little stinker!" Sessions said before joining Mueller to announce the start of Saturday Night Live.
Although SNL has cast McKinnon in the past as Mueller, the show enlisted De Niro back in April to play the former FBI director. De Niro also played the part again in Tina Fey's May episode.
Trump asked for Sessions' resignation on Wednesday, the day after the 2018 midterm elections. Trump was reportedly not happy when Sessions recused himself from handling the Russian investigation, which opened the door for Deputy Attorney General Rod Rosenstein to appoint Mueller Special Counsel. Whitaker made his opposition to Mueller's investigation clear in comments before he was appointed Acting Attorney General.
De Niro has been a vocal critic of the Trump Administration. He was among the Trump critics who received a suspicious package before the midterms. A package believed to be a pipe bomb was sent to his Tribeca Productions office.
"I thank God no one's been hurt, and I thank the brave and resourceful security and law enforcement people for protecting us," De Niro said in a statement. "There's something more powerful than bombs, and that's your vote. People MUST vote!"
Photo Credit: NBC