The writer and showrunner, who will depart the BBC cult show next year, praised Tovey in serialised emails appearing in The Times.
"He's going to be huge, that man," Davies wrote. "He's amazing. I think I'd make him the eleventh Doctor."
Tovey, 26, previously appeared as Midshipman Frame in the 'Voyage Of The Damned' episode of the programme. His other credits include Gavin & Stacey and Ashes To Ashes.
Davies's correspondence also revealed that his proposal for J.K. Rowling to cameo in Doctor Who was shot down by Tennant.
"David doesn't like the J.K. idea," he noted. "He thinks it sounds like a spoof, so we've paused slightly, wondering whether to win him round or just abandon something that he's not going to be happy with.
"We've got to keep him happy. He keeps us happy. Plus, he might be right. So that idea has parked."