Peter Davison has revealed David Tennant took ages to pluck up the courage to ask his daughter Georgia Moffett out.
David and Georgia are now married with a two-year-old daughter after meeting on the set of Doctor Who.
But former Time Lord Peter revealed to the Reader's Digest his surprise when his daughter introduced him to David, and her frustration at how shy the former Doctor Who star turned out to be.
Peter explained: "I was in Spamalot in the West End, and Georgia said she was going to come and see the show, and she was bringing someone. It turned out to be David Tennant. I said, 'Are you going out?' And she said, 'Oh no, just friends' - which was true at that time.
"He was actually very shy about getting round to asking her out. They'd meet up and go to the theatre, and it was quite a while before he plucked up the courage.
"She said, 'I don't understand. If he's interested, why he doesn't just ask me out? He's playing Doctor Who!' And I said, 'It doesn't really make any difference. You're either that sort of person or you're not.' It doesn't matter if you're the most famous guy in the world if you're self-effacing. I knew how he was feeling, of course."
The 61-year-old Law And Order star also confessed his own nerves when he was cast as the fifth Doctor in the hit BBC series, as he was the first star of the show who had grown up as a fan himself.
Peter revealed: "I watched the first five or six years of the show avidly. So when I started in 1981, I was daunted about following Patrick Troughton and William Hartnell.
"I was much younger than any previous Doctor and the producer said to me, 'You need an outfit that's eccentric but British.' It seemed to me that the cricket jersey was an obvious choice, since it was sportier, younger."
:: May's issue of Reader's Digest is out on Tuesday April 16.