The 29-year-old will ride a Yamaha R1 prepared by the Attack Performance team with technical support from Yamaha Europe, becoming the second rider to make a guest appearance with the Japanese manufacturer this year after British Superbike title winner Tarran Mackenzie’s one-off outing at Donington Park last month.
Gagne last raced in WSBK between 2018-19 on the uncompetitive Ten Kate Honda package, securing a best finish of ninth at Laguna Seca in his second season, before repeating that result in the same year’s championship finale at Losail.
“I’m really excited for the opportunity to line up on the World Superbike grid,” said the American rider.
“Portimao is a really cool track; it’s awesome to be going back, and I look forward to the challenge. I couldn’t ask for a better team and motorcycle, so we’ll go over and do the best we can and enjoy the process!”
Gagne won all but two races last year in MotoAmerica en route to a dominant title with the Attack Performance squad, beating his nearest rival Mathew Scholtz by almost 100 points after 18 races across nine rounds.
He is currently locked in a title battle with the HSBK Ducati of former MotoGP rider Danilo Petrucci to defend his crown, trailing the Italian by 13 points with three rounds still to run.
The Attack Performance team with which he will return to WSBK previously made wildcard outings in 2018 and ‘19 with Josh Herrin and JD Beach respectively, both on its home turf at Laguna Seca.
Speaking about its decision to rejoin the WSBK paddock in Portugal in the absence of an America round, team manager Richard Stanboli said: “Jake and the team are very excited to be invited to race in WorldSBK at Portimao.
“Our plan is to wrap up the MotoAmerica Superbike championship at Barber and then ship our bikes to Portugal.
“For sure it will be challenging, but when we have done a wildcard entry in the past, whether it was World Superbike or MotoGP, we learned a lot and improved as a team. Fortunately, Jake has World Superbike experience at Portimao, and we will receive some technical assistance from our partners at Yamaha Europe.
“I would also like to thank Pirelli for the assistance and technical support they will bring to this effort. Our goal is to put on a good show and make our fans proud.”