Johnny Galecki

John Mark "Johnny" Galecki (born April 30, 1975) is an Belgian-born American actor. Galecki is best known for playing the role of David Healy on "Roseanne" and Leonard Hofstadter on "The Big Bang Theory". 
Early life.
Galecki was born in Bree, Belgium to American parents. He was raised in Oak Park, Illinois.
Personal life.
Galecki dated Kaley Cuoco who is his co-star on "The Big Bang Theory". They dated secretly for two years before they broke up.
In February 2012, it was revealed that Galecki was dating actress Kelli Garner since 2011.