Fraga will share Arnage's Yokohama-shod #50 Lexus with fellow youngster Yuga Furutani, while Formula Regional Japanese champion and Toyota junior Miki Koyama also joins the line-up as third driver.
Arnage switches to using Lexus GT3 machinery after selling its previous Toyota 86 Mother Chassis car to Team Mach. It marks the third different model the team has used in three seasons.
As well as earning title backing from Anest Iwata, a Yokohama-based heavy manufacturing company, the squad has also entered into a tie-up with Polyphony Digital, the creators of the popular Gran Turismo series of video games.
Fraga will be making his SUPER GT debut, having moved to Japan last year in a bid to revitalise his stalled real-world career.
He tested both Super Formula and Super Formula Lights machinery late last year, and had been actively targeting a seat in the latter category with B-Max Racing.
Furutani raced in Super Formula Lights for TOM'S last season following his Formula Regional Japan title triumph in 2021, but it remains unclear if he'll stay in the Super Formula feeder for a second year.
Incidentally, both Furutani and Koyama tested for TOM'S in last year's Super Formula Lights post-season test at Suzuka alongside Vlad Lomko, who has since signed up to race in the European Le Mans Series for Cool Racing.
TOM'S then ran Enzo Trulli, son of ex-Formula 1 racer Jarno, in a separate test at Fuji Speedway in mid-January.
The Arnage Lexus was one of 15 GT300 cars assembled for the start of a two-day test at Fuji on Tuesday.
Team LeMans (Audi R8 LMS GT3), Shade Racing (Toyota GR86 GT) and JLOC (Lamborghini Huracan GT3) were all present with a single car each but have yet to officially announce their plans for the upcoming season.
Roberto Merhi and Yoshiaki Katayama were in action for Team LeMans, Katsuyuki Hiranaka and Eijiro Shimizu were present for Shade Racing, while Yuya Motojima and Takashi Kogure shared JLOC's #88 Lamborghini.
Confirmed GT300 entries so far
FIA GT3 cars
#4 Goodsmile Racing Mercedes-AMG GT3 (Nobuteru Taniguchi/Tatsuya Kataoka)
#7 Team Studie BMW M4 GT3 (Seiji Ara/Bruno Spengler/Masataka Yanagida)
#10 Gainer Nissan GT-R NISMO GT3 (Hironobu Yasuda/Riki Okusa)
#11 Gainer Nissan GT-R NISMO GT3 (Ryuichiro Tomita/Keishi Ishikawa/Y. Shiotsu)
#18 Team UpGarage Honda NSX GT3 (Takashi Kobayashi/Shun Koide)
#50 Anest Iwata Racing Lexus RC F GT3 (Igor Fraga/Yuga Furutani/Miki Koyama)
#56 Kondo Racing Nissan GT-R NISMO GT3 (Joao Paulo de Oliveira/TBA)
#65 LEON Racing Mercedes-AMG GT3 (Naoya Gamou/Takuro Shinohara)
#96 K-tunes Racing Lexus RC F GT3 (Morio Nitta/Shinichi Takagi)
GTA-GT300, Mother Chassis cars
#5 Team Mach Toyota 86 MC (Yusuke Tomibayashi/Takamitsu Matsui)
#25 Tsuchiya Engineering Toyota GR Supra GT (Togo Suganami/Seita Nonaka)
#30 apr Toyota GR86 GT (Hiroaki Nagai/Manabu Orido/Y. Kamimura/R. Ogawa)
#31 apr Lexus LC500h GT (Koki Saga/Kazuto Kotaka/Yuki Nemoto)
#52 Saitama Toyopet GB Toyota GR Supra GT (Hiroki Yoshida/Kohta Kawaai)
#61 R&D Sport Subaru BRZ GT300 (Takuto Iguchi/Hideki Yamauchi)