Steve McFadden's former lover was arrested on Valentine's Day following a fiery row with the EastEnders star.
Dr Rachel Sidwell was taken into custody at 7.30 am and spent the most romantic day of the year being questioned by police after Steve told cops she attacked him in his car.
The actor, best known for playing hard man Phil Mitchell in the BBC soap, claimed to have scratches on his back and shoulders after the 45-year-old dermatologist allegedly assaulted him on Sunday.
A Scotland Yard spokesperson confirmed on Tuesday: "This morning, a woman in her 40s was arrested in connection with the investigation."
Rachel was released from custody at 6.30pm on Tuesday night.
Steve has had his fair share of drama with Rachel - they got together in 2008 when she left her surgeon husband to move in with the soap star.
However, the year-long relationship went pear-shaped and Rachel was arrested just days after their 2009 split on suspicion of criminal damage when scratches appeared on Steve's moped.
The dad-of-four was then arrested in November 2010 amid harassment allegations, although the matter was later dropped.
The former couple have a two-year-old daughter together.