Hugh Jackman said he really was done playing the character of Wolverine after Logan (2017). He then said he regretted that statement after watching the first Deadpool movie and expressed to Ryan his interest in the two characters meeting on the big screen. When asked why he chose to return for this film, he simply said, "I just wanted to do it, and I felt it in my gut", adding that he wanted to have the best possible time ever on a movie set together with Ryan Reynolds. Likewise, Reynolds wanted to work alongside Jackman since the first Deadpool film and was saddened when he (Jackman) retired from the role.
Ryan Reynolds said that he and the makers purposely asked for a lower budget than Disney was prepared to offer them, remembering that the first Deadpool (2016) was such a success because they had constant time and budget limitations, which fostered an atmosphere for great creativity.
Kevin Feige was originally against bringing back Hugh Jackman as Wolverine, as he was concerned that doing so would undermine the events of Logan, a movie Feige held in very high esteem. He eventually relented once it was confirmed that this film would focus on a different variant of Wolverine, combined with Jackman really wanting to return to the role. His only stipulation for Jackman coming back was that Logan had to be depicted in his classic yellow and blue costume.
Hugh Jackman had to bulk back up into Wolverine shape. Although he'd maintain a fitness regime for health reasons, he slimmed down due to singing and dancing for eight shows a week in a revival of "The Music Man", and needed to gain a large amount of muscle mass in the short gap between the end of the musical run and the start of principal photography.
Hugh Jackman said, "I was on my way, I was just driving, and literally, just like a bolt of lightning, came this knowing deep in my gut that I wanted to do this film with Ryan. For Deadpool and Wolverine to come back together. I swear to you, When I said I was done, I really thought I was done. But in the back of my head, ever since I saw 'Deadpool' 1, I was like, 'Those two characters together.' I knew it, I knew the fans wanted it ever since I put on the claws, people talked about these two. So, that had always been there, but I just knew. And I literally couldn't wait to arrive. Soon as I arrived, I rang Ryan. And I just said, 'Let's do it.' Like, I hadn't rung my agent, no one. I had to ring my agent and said, 'Oh, by the way, I have just committed to a movie.'"