The sci-fi drama's new lead will "take the show in an interesting [new] direction", said the actress, who plays companion Clara.
"He's going to be so different to Matt [Smith]," Coleman hinted. "It will be a different show next year. We have a bit of a gap before we start filming the new series, so I have time to get my head around it all.
Me and Peter will get together before Christmas to start rehearsing and the scripts will start coming in."
The 27-year-old added that Capaldi's casting "makes sense" following Smith's four-year tenure as the Doctor.
"It's funny as I don't think he was one of the names that was originally being speculated about," she said. "It wasn't until the week before [the official announcement] that his name came up."
Matt Smith - who will depart Doctor Who in this year's Christmas special - has described his successor as an "incredible" choice.
Doctor Who's festive special 'The Time of the Doctor' will air on Christmas Day (Wednesday December 25) at 7.30pm on BBC One.
Matt Smith's Doctor Who exit was brutal, says Jenna Coleman
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