The American Sniper star appeared alongside Bradley Cooper on The Graham Norton Show last week (ends01Nov15) and she was the only celebrity not sporting the poignant symbol, which is worn in the run-up to Remembrance Day (11Nov) to honour those killed in battle.

Sienna came under fire on social media for apparently disrespecting fallen servicemen, and she was also criticised by British defence minister Sir Gerald Howarth, who said, "There should be no excuse for not wearing one so we can honour the war dead."

However, she has now spoken out to insist she intended to wear the red flower on the show but had to remove it just before the cameras rolled because its fastener was ruining her dress.

"I had a poppy on, funnily enough, and I was wearing a dress that was like crepe paper basically and as I was going on I looked down - it was tearing at the dress and they'd said my name and so I whipped it (the poppy) off," she tells U.K. TV show Good Morning Britain.

"It's unfortunate it's been made such a huge kind of... it's really snowballed apparently, and of course I don't think there is anyone in this country that isn't grateful and respectful and never would want to cause offence and wear a poppy all the time but people kind of focus on things enough to pick at the negative. It seems a little extreme."

She is also concerned about another interview she recorded in advance with Cooper to promote their new film Burnt, as she is not certain either of them wore a poppy for that as well.

Sienna adds, "Also, there's another show I'm worried about coming out because we pre-recorded it, where we are probably not wearing poppies but some of these things are filmed weeks before they air. But you can't please everyone and I meant no disrespect. Of course I didn't."