Amanda Seyfried boarded a plane with a knife in her pocket.

The 'Lovelace' actress took to Twitter to confess that she had boarded a flight on Friday (14.03.14) with a Swiss army knife in her pocket but wasn't aware that she had been in possession of the dangerous object until she had already been seated on the plane.

She wrote on Twitter: ''Dear TSA: This Swiss Army knife wasn't detected through security and I unknowingly carried it on board. Scary! (sic)''

In March of last year, Transport Security Administration announced retractable knives containing blades shorter then 2.4 inches and narrower than 5 inches at the widest point, would allowed on board in passengers hand luggage, with the restrictions to be lifted the following month.

However, by June, TSA announced it had abandoned the plan in the face of fierce congressional and industry opposition.

Meanwhile, Amanda has credited her boyfriend Justin Long for helping to boost her confidence.

She began dating the 'He's Just Not That Into You' actor, 35, last summer and admitted she ''can do no wrong'' in his eyes.

Amanda told the February issue of US InStyle magazine: ''You've got to find someone who makes you feel like you could gain 20 pounds and he'd still look at you the same. But as an actress it's easy to feel insecure.''