Simpson and Willis will be making to make history as if they win it will be titles #7 and #5 respectively.
Not surprisingly, GB 800m runner Kyle Langford (the runner Bett beat out for world bronze by just .04) hasn't reacted too happilly on Twitter.
"There will be nerves, definitely there will be nerves, it's not like it's a charity game any more."
Coach Mike Mulvey: "Look, he's doing OK. The thing that we're asking him to do is something that he's not done for quite a number of years. He's got rudimentary skills, there's no problem about that, it's about being able to do it at the speed that we do it. ... What the lads in the office are telling me is there could be 10,000, 12,000 people here (on Friday) so that's quite unbelievable for a pre-season game. But I welcome it because it puts us under a little bit of a spotlight."
Italy's former world indoor champ Gianmarco Tamberi impressed with 2.33m for second in his highest jump since coming back from his tragic ankle injury of 2016.
The 2018 DL season is over on Friday.
This will be big for African testing as samples will no longer need to be transported to Europe or South Africa. This will allow for more blood tests which previously were extremely difficult.
Bolt's coach says he has "rudimentary skills" and added, "I imagine he'll get some minutes."