Shepard, who officially turned 44 years old Wednesday, was fielding questions during an "Ask Dr. Dax" segment when Bell stood up in the audience and asked what he recommends getting a loved one for their birthday.
"Please, please please give that person love and support for 11 years. Give them two beautiful baby girls -- and you're good," Shepard responded while tearing up.
"You're crying, too!" Bell responded with watery eyes. "I love you."
DeGeneres then presented Shepard with a birthday cake onstage. A clown popped out of the cake to scare the actor and Bell.
"I started getting suspicious," Shepard said of his reaction. "Get out of here, you little rascal!"
Shepard and Bell married in October 2013 and are parents to two daughters, 5-year-old Lincoln and 4-year-old Delta. Shepard posted a rare photo of his family on Instagram this week.
"Denim on denim on denim on denim on denim on denim on denim gawking at a hot rod wagon," he said of his family's denim outfits. "@@jaylenosgarage would be SOOO thrilled :)."