The 23-year-old Gossip Girl actress is the face of the label's Mademoiselle handbag, but said that she plans to leave the designs to the professionals.
She told WWD, 'I've been asked about that but I have such a respect for fashion and such an appreciation for it that, if there are people like Karl Lagerfeld out there designing, who am I?'
Talking about the moment she first met Karl, she added, 'I was wildly intimated. He's an incredibly intimidating person because he's so accomplished and he's such a genius, but the moment you meet him, he doesn't try to intimidate you.
'He's so kind and humble and alive and passionate. I love and respect him so much.
'I wouldn't want to work with anyone else. The moment I met him I said, 'I don't want to do a campaign unless it's Chanel'. So it's nice that we get to work together.'