Adding regular Skype user to Skype for Business conference call

[jahongir abdurahmonov]

Can we add regular Skype contact to the Skype for Business conference call? I know that SfB and regular Skype users can have a call peer to peer, however, I am not sure if regular Skype user can join an conference call where all other users are using Skype for Business. 

[#2]

Simple answer is no :)

Best would be to add them trough PSTN or invite them to a Skype for Business meeting so they could join as a guest.

[#3]

I agree with @AlexanderHolmeset. Invite users as guests where they join using Skype for business web app (or Skype for business meeting app), or via dialin conferencing.