The 19-year-old midfielder left Manchester United after his contract expired this summer.
"They say it is a promise, but for us it is already a certainty!" his new club wrote on Instagram.
"With all his training at Manchester United, where he arrived at just 6 years old. Angel always stood out from the crowd. In 2015 he was the best player in the MU premier Cup tournament, in 2016/2017 he made his debut in the RED team, replacing Wayne Rooney, against Cristal Palace, becoming the youngest player to take the field for the Red Devils.
"Angel Gomes, son of the Under 20 World Champion, by Portugal Gil Gomes, also has a remarkable history at the level of the national teams, his being at the service of the English national team. He passed through all levels (Under-16, 17, 18 and 19), having, in this course, been champion of the Under 17 world.
Angel Gomes confirmed by Boavista, currently 12th in the 18-team Portuguese league #mufcpic.twitter.com/ql7nRae4TW
— Samuel Luckhurst (@samuelluckhurst) August 5, 2020