For the first time in 20 years, Graham Norton is taking a break from his BBC chat show.
It comes as Graham is away commentating for the Eurovision Song Contest, which he has done since 2009.
While Paloma Faith was originally slated as one of the guests set to appear, she no longer will appear.
Viewers will see Peter Crouch and David Walliams on the sofa instead.
They are joining actors Luke Evans and Gwendoline Christie on the line-up as Sam Fender brings the music.
Graham has jokingly issued a warning to Jack ahead of his presenting stint.
He said: “I’m thrilled to know that I am leaving the show in Jack’s capable hands. He is bound to do an amazing job.
“I should warn him not to get too comfortable in my chair though, because like a slightly fey Terminator, I’ll be back.”
Meanwhile, Jack said he was “honoured” to have been asked to step in.
“I was so honoured Graham asked me to do this from him,” Jack commented.
“The thought of stepping into his huge showbiz boots fills me in equal measure with fear and excitement.
“Worst case, I will make everyone appreciate just how lucky we are to have him.”
This year’s Eurovision is being held in Tel Aviv after Israel won the 2018 instalment of the competition.
The UK’s entrant is Michael Rice who will perform the song Bigger Than Us on Saturday.
He may be familiar to viewers after winning the first series of BBC contest All Together Now.
Michael recently appeared on Lorraine to talk about how he was approaching the competition.
The 22-year-old revealed he wasn’t expecting to win.
He told host Lorraine Kelly: ‘We have to be realistic.
“But I’m going in there with a winner’s head on, either way, to make sure that we get on the left-hand side of the board if we can.”
The Graham Norton Show continues tomorrow at 10.35pm on BBC One.