Just two nights after debuting in the title role of a new production of Hamlet, David Tennant was back at the theatre.

But this time the actor wasn't treading the boards.

Instead, Tennant and his Doctor Who co-star and girlfriend Georgia Moffett were lending moral support to another star of the hit TV show, Catherine Tate, appearing in play Under The Blue Sky.

Love lord: David Tennant leaves a West End theatre with his girlfriend Georgia Moffett

When the private couple left the Duke Of York's Theatre in the West End district of London they made a mad dash for a taxi.

They have been dating for the past couple of months.

Miss Moffett, a 23-year-old single mother who recently dyed her hair jet black, is the fourth Doctor Who colleague Tennant has romanced. Bizarely, she plays his onscreen daughter on the show.

In April, Tennant was reported to be dating second assistant director Jennie Fava, who moved to Cardiff to help film the latest series of the hit BBC1 programme which has been running since 1963.

Weeks earlier, he split with another BBC Wales staff member, Bethan Britton, after a four-month relationship.

When the pair met she had been working in the corporation's contracts office in the city.

Searching for a taxi: The couple leaves the Duke of York theatre

He was also linked to Kylie Minogue after the pop star appeared in Doctor Who's Christmas special, in which they passionately kissed.

Last October, Tennant parted ways with actress Sophia Myles after a two-year relationship, following her move to Hollywood.

They, too, met on set - when Miss Myles played Madame de Pompadour in a 2006 Dr Who episode.

Miss Moffett played the Time Lord's child Jenny in episode six of the most recent series entitled The Doctor's Daughter and while it was a one-off appearance, the opportunity for her to return in later shows has been left open.

The actress, who has a six-year-old son named Tyler from a previous relationship, revealed after first meeting Tennant: 'David is dishy, isn't he?

'He's not only a good-looking but he is such a lovely, sweet guy.'

Mr Tennant has been nursing his personal heartache after his mother Helen died after a five-year battle with cancer last summer.

More than just co-stars: The couple in late June before Miss Moffett dyed her hair