Rachel Bilson was stopped by airport security because they thought she was too young to be travelling alone.

The 31-year-old actress was stopped at Los Angeles International Airport because an official thought she looked like a child but the petite brunette is still worried about getting older.

The 'Hart of Dixie' star told the March issue of Women's Health UK: ''I know I look super young. I was flying back home into LAX the other day and the security guard at the airport stopped me and said, 'Honey, where's your family?' And I'm like, 'I'm 31!'

''Maybe when I'm 40 I'll appreciate it, but as I get older and get wrinkles I'm worried it'll be, 'She's the weirdest-looking teenager I've ever seen.'''

Emma Watson recently revealed that she was also stopped at US immigration because officials thought she was a child.

The 22-year-old actress was stopped at JFK airport in New York where she was questioned by officials at passport control who believed the youthful looking 'Harry Potter' star was an unaccompanied minor.

She tweeted: ''Passport control: 'unaccompanied minor?' Me: 'sorry?' Passport control: 'where is ur guardian?' Me: 'I'm 22!!!!!! #neverwearingbackpackagain

''The really sad thing is that this is not the first time this has happened (sic).''

A source close to the actress later revealed: ''Emma was mortified. Not only did they not know who she was they thought she was a child. It was very embarrassing but she managed to awkwardly laugh it off.

''The Americans are very serious about who they let in and out of the country. If young kids are thought to be on their own, it poses a massive problem.

''Luckily, Emma managed to convince them how old she is.''