Want to bring outsider client on Fiverr

[asimseobacklink]

Hi, 

I hope all of you are fine and well. I want to ask a question that I have a client outside of the fiverr. I also have his mobile whatsapp number. I do all of the convesation via whatsapp. currently he makes his new site. very soon he will published article for backlinks and for this I will do guest posting of that client and published his 5 to 10 articles on different sites. Can  I bring this client to fiverr so that I take order from him via fiverr but I will do mostly of the conversations on whatsapp because he did not use fiverr. 
Is it legal or illegal for me because I already have his contact number and whats happen if he gave me order and after that I conversate outside of the fiverr via whatsapp etc. 

How will I inform to fiverr that I already have this client whatsapp number.

thanks

[milos_siena]

It's okay to promote your gigs outside Fiverr and bring potential buyers. But this user needs to create an account on our platform. I assume that your conversation from the start was outside Fiverr since he hasn't got an account. That is okay if he creates a  profile and orders from you. Just have in mind not to take the Fiverr buyers off Fiverr.