Freema Agyeman was born in 1979 in London to a Ghanaian father and Iranian mother. She made an appearance in the Crossroads Revival in 2003 (as one of the hotel staff) and like many a British actor, has been in The Bill (in her case, three times as two different characters).
However, her most famous role at the moment is as Martha Jones in Doctor Who and later in spin-off show Torchwood. Performing a You Look Familiar, she had previously played a Cyber-controlled Adeola Odoshi in "Army of Ghosts", where she ended up put out of her misery by the Doctor. Three episodes later, in "Smith and Jones", she made her first appearance as Martha.note The two characters being played by the same actress was explained away by establishing that Adeola was Martha's cousin.
Also a star of Law & Order: UK, alongside co-Sci-Fi Actor Jamie Bamber. And former Doctor Peter Davison. She plays Larissa, mentor to the young Carrie Bradshaw (AnnaSophia Robb), in the Sex and the City prequel The Carrie Diaries. She's currently appearing in the online series Sense8.