The Sin City actress reportedly turned to fags to ditch her pregnancy weight after giving birth to daughter Haven in 2011.
They met when cast in a touring production of the seagull in early 1995 and began living together shortly afterwards.
She revealed the guy in her life on Instagram on November 24, 2019.
Beckinsale later married director Len Wiseman in 2003 and adopted her as a stepdaughter.