The former Doctor Who star explained the process of voicing Charles Darwin in the animated comedy during a recent interview.
"It's very unusual because you're aware that the process is going on for years, this film has a long gestation period. We actors came and visited it every now and then. Once every three months we'd come in and have a recording session," he recalled, reports Flicks and Bits.
He continued: "That spread over, I don't even know how long I was working on it, certainly over a year, maybe even two years. It was a long process that the actors would just revisit every now and again.
"We'd come back and be very excitingly told that there's five minutes of footage, now there's fifteen minutes of footage. It was clearly a laborious and fastidious process, but it is so exciting to be any contributing factor to that."
Tennant added that he was so impressed when he saw the finished film for the very first time.
"What's very exciting is to be a part of the finished product, you have that in mind the whole time," he explained.
"The actors aren't the stars of this film, the stars of this film are the animators and the extraordinary things they can do with the extraordinary beautiful creations they put together, the wonderful world they created and indulged with all the creative brilliance Aardman [Animations] can throw at it."
Tennant's co-star Martin Freeman recently joked the animated The Pirates! In An Adventure With Scientists is not the kind of film that inspires him as an actor, but he loved voicing a character in the movie regardless.
Hugh Grant and Salma Hayek also star in The Pirates! In An Adventure With Scientists, opening on March 28 in the UK and on April 27 in the US.
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Watch a trailer for The Pirates! In An Adventure With Scientists below: