Monday's deadline day saw Jese join Sporting on a season-long loan deal from Ligue 1 champions Paris Saint-Germain.
The loan includes a purchase option for former Real Madrid forward Jese, who is contracted to PSG until 2021.
Five-time Ballon d'Or winner Ronaldo emerged from Sporting's youth system before joining Manchester United in 2003 and Jese said: "I am very happy for the opportunity Sporting CP is giving me. It is a historic club in Portugal.
"I have a friend named Cristiano Ronaldo who has always told me very good things about this club, which created him from a young age. I am very excited to start training with my colleagues.
"I have seen the players the team have and I think we can do something important. We will fight for all competitions. With joy and work we can achieve good things."
On Juventus superstar Ronaldo, Jese, 26, added: "He told me it was a very important club for him and he was very fond of Sporting CP."
Sporting also signed winger Yannick Bolasie on loan from Premier League outfit Everton on Monday.
The Primeira Liga club – who managed to keep captain Bruno Fernandes despite reported interest from Real Madrid – are fifth in the league after four games.