The 23-year-old Gossip Girl star - who is reportedly dating Leonardo DiCaprio - said that she has no intention of joining the micro-blogging site.
'People ask me why I don't tweet. Honestly, I'm so sick of myself,' she told Glamour magazine.
Having previously dated her co-star Penn Badgley, she insisted that it is never weird seeing him on set because things didn't end badly.
'Every relationship you have, you're learning and growing and taking something from that. So for me, it's never been too dramatic of a thing when something ends,' she explained.
'I have a strong sense of myself. That gives me a sense of security, you know. If I define myself by things that are always changing, like the public's opinion, or what I'm wearing, or what job I'm doing, there's no stability in that.'
Despite recently fronting a fashion campaign for Chanel's Mademoiselle handbag range, Blake admitted she hates being the focus of attention for people.