Israel Folau will make his test return when he plays for Tonga against Fiji in the Pacific Nations Cup on Saturday.
The 33-year-old, a fundamentalist Christian, won 73 caps for Australia but had his contract terminated in 2019 after posting a homophobic tweet.
A change in World Rugby's rules last year allowed him to switch allegiance to Tonga.
Folau was listed as 'Isileli Folau' by Tonga and named on the right wing for the match in Suva.
"It's been awesome to be able to come back and have the opportunity to connect with the boys and with the culture as well," Folau said in a video message.
"A big part of that is our faith in God as well."
The change in World Rugby rules meant that from January 2022 a player could represent a different country after a stand-down period of three years and move to a nation of their, their parents' or grandparents' birth.
Folau has also played rugby league and Australian rules football.
He had a spell at rugby league side Catalans Dragons but was released from his contract in June 2021.
Folau returned to rugby union when he joined Japanese Top League side Shining Arcs last year.