Yes you will! Interest accrues on a daily basis the day after you fund your account. You will receive an interest payment for the number of days the balance was in your Interest Account.
For example, if you fund on the 15th, you will earn ~15 days worth of interest.
If you fund on the 20th, you will earn ~10 days worth of interest.
Each instance is prorated based on the number of days that the funds were held in the account.