Doctor Who star David Tennant is rumoured to be in a romantic relationship with his co-star Georgia Moffett, who is his on-screen daughter.
The pair were photographed leaving his north London home on Saturday morning after spending the night there.
They arrived at her flat on Saturday night and Tennant, 37, did not leave until 11am the next morning.
Miss Moffett, 23, who has a six-year-old son, is the real daughter of former Doctor Who Peter Davison.
A friend of Miss Moffett’s said: “They have been going out together for a while now but meet up at each other’s houses so as to avoid being spotted by Who fans.
“David can’t really go anywhere without attracting attention and it’s early days so they don’t want any distractions or fuss made about what’s going on.
“It started with some friendly dinner dates but has progressed quickly and they are now in a serious relationship.
“Even with his busy schedule, David is making a lot of time to spend with her, so he must really like her.”
The couple met while filming in Wales. Miss Moffett has described the encounter.
She said: “It was winter when we filmed and I was wearing very little so you can imagine how cold that was.
“David kindly lent me his jacket between takes.”