Johnny Galecki Used a Fake Wall on 'Big Bang Theory' Set to Stick His Chewing Gum for 12 Years

See Johnny Galecki's Hilariously Sweet Tribute to "Worldwide Adored" Ex Kaley Cuoco

Johnny Galecki shares a throwback snap and calls while wishing Kaley Cuoco a happy belated birthday

Kaley Cuoco and Ex Johnny Galecki's Friendship Through the Years