From PEOPLE Magazine Click to enlarge
Alex

O'LOUGHLIN

The upside of having an 'O' name? "I have far less chance of getting pocket dialed since 'O' falls in the middle of the phone book," says the Hawaii Five-O star, 35. "But since my first name starts with A, I get pocket dialed anyway."

O'

BEFORE AN IRISH SURNAME MEANS "DESCENDANT OF"

Chris

O'DOWD

Common nicknames? "In college I got called Chris 'Wellen-Dowd,'" says the Bridesmaids breakout, 32. "Also, 'O'Loud,' possibly for shouting the other nickname at strangers."

Jerry

O'CONNELL

"My daughters are just starting to say their last name, but they pronounce it 'Opa-Connell,'" says the actor, 37.

Conan

O'BRIEN

"Trying to trace the name O'Brien in Ireland is like going to a deli and asking for Abe," says the 48-year-old late-show host. "All I know is that we're prone to depression and are said to like starch."

Chris

O'DONNELL

"As a kid my nickname was 'Little O'D,'" says the NCIS: Los Angeles star, 41. "Now it's 'COD.'"