Sam Taylor-Wood and Aaron Johnson
07/29/2011 at 04:00 PM EDT
Aaron Johnson is getting ready to pull double-daddy duty – his fiancée, filmmaker Sam Taylor-Wood, is expecting the couple's second child, her rep confirms to PEOPLE.
star, 21, and Taylor-Wood, 44, whose romance raised eyebrows
because of their 23-year age difference, are already the proud parents of a baby girl, Wylda Rae
, who just turned 1.
After stepping out together
as a couple last spring, Johnson defended their relationship. "I've got a wonderful woman. I'm an old soul, and she's a young soul."
Taylor-Wood, who also has two daughters from her first marriage to art dealer Jay Jopling, met in 2009 on the set of her directorial debut, Nowhere Boy
Reporting by SIMON PERRY