Dynamically Expanding VHD with BitLocker Enabled

Hello All...........If I am using a Dynamically Expanding VHD on a Virtual Machine based on Hyper-V, VMware, etc.; and I enable OS BitLocker on it, would it take up all the size of the VHD i.e. 100 GB or 20 GB which is the actual size of VHD?

Thanks in advance.