For Brent Spiner, the return to Star Trek was a surprise to him as he believed that he was finished with it after Data died in Star Trek: Nemesis.
Speaking at Destination Star Trek: Birmingham, Spiner said that “I thought it made a lot of sense and because I was also part of the team that wrote the story, I knew that was going to happen.
“We had been told in almost no uncertain terms by Paramount Pictures, that this was going to be our last film, so I thought it made a lot of sense to leave the audience with a really big, dramatic, emotional moment at the end of the film. If that’s the last time you were going to see the character then that’s the way it should be, you know…at the time I thought it was the right way to go.”
But a surprise phone call changed that. “I assumed they wanted me to play Picard because I can,” he said, joking with the crowd in attendance. “I’ve gotten younger. I’ll last longer.
“So they said, ‘Well, would you have any interest in playing Data again?’ And I said, ‘Make me an offer I can’t refuse.'”
Source: Star Trek.com