As long as your DNS records on Cloudflare match the records on your current nameservers, it will be fine. Just pay particular attention to DNSSEC, you might want to disable it before you switch and enable it only once your domain loads fine on Cloudflare.
Thank you for your response. Where do I configure DNSSEC?
Also, my current nameserver entry is in digitalocean but that is not my Domain registrar. So, will adding cloudflare nameserver in digitalocean do the job or it will need to be done on Domain registrar?