The pair were coupled up in last weekend's launch show and have been working hard in training on their first performance.
The first Strictly songs and dances were revealed last week, with Jonnie and Oti dancing a Waltz to When I Need You by Luther Vandross.
In this video we see Jonnie take his very first steps in training.
Jonnie says: "It wasn't as long as I thought. We've done eight hours and you get into it, it goes so fast.
— BBC Strictly✨ (@bbcstrictly) September 18, 2017
"The morning I felt went well but in the afternoon we hit a bit of a dip. Nothing seemed to go in, just mental block."
He admitted the "intense learning" was tough: "I think I'm struggling to keep up with the mental aspect."
Oti tells cameras: "First day with Jonnie is complete and I'm so happy. Jonnie is a great pupil. I love the fat he gets into what were doing 100% with all concentration.
"I love the fact that he actually cares and gives his all from the beginning to the end."
Jonnie adds: "It's weird, it's like every time it starts getting easier it starts getting harder straight away."
Strictly Come Dancing's live shows this year begin next Saturday on BBC One.
This week the celebrities can relax slightly as no one will be going home at the weekend with no elimination for the opening show as usual.
However they will still be marked by judges Bruno Tonioli, Craig Revel Horwood, Darcey Bussell and Shirley Ballas and those scores will carry forward to the next week where one unlucky celeb WILL get the boot.
Strictly Come Dancing 2017 begins its live shows this Saturday, September 23 starting at 6:25PM.