Celik's move to Turin caught many in Italian football off guard, with Juventus swooping in on a free transfer after AS Roma appeared close to agreeing fresh terms with the Turkey international, whose previous contract had expired.
Speaking to Juventus's official channels to introduce himself to supporters, the 29-year-old described his first impressions of life at the club.
"How was it meeting the squad?" he was asked.
"I met the coach and my team-mates," Celik replied. "It was a nice moment and it helped me break the ice. I bonded with my team-mates straight away. It was a nice moment for me. I'm happy to be here."
Asked how he expects to fit into Spalletti's system, Celik pointed to conversations he has already had with the Italian coach, who took over at Juventus this summer.
"Obviously I spoke a little with the manager," he said. "He explained to me how he intends to play. And he's certainly a great coach, a successful manager in Italy. My friends who have worked with him have also said he's an exceptional coach, a great professional who gives a lot to his players. That's why I believe I'll do well with him."
Celik, who can play at right-back, wing-back or as part of a back three, also revealed he had already heard from Yildiz, one of Juventus's brightest young talents and a fellow Turkey international.
"He sent me a voice message," Celik said. "He told me he was very happy about my arrival and that we'll do great things together. I care about him, he's a great person. He has an extraordinary personality, he's the future of Juventus. I'm happy to be here, forza Juve."
Celik spent four seasons at Roma after joining from Lille in 2022, making more than 150 appearances for the club, and his sudden departure has left Gian Piero Gasperini's side needing to find fresh options at right-back this summer.
Juventus moved quickly to complete the deal once it became clear Roma's renewal talks with the defender had stalled, with the club's new sporting leadership taking advantage of a free transfer to add an experienced, versatile defender to Spalletti's squad without any transfer fee involved.
Celik, capped regularly by Turkey, offers the kind of positional flexibility that Spalletti has previously valued in his sides, able to operate across multiple roles within either a back three or a back four depending on how his new manager chooses to set up the team.