(as) (a)like as (two) peas in a pod
Said of two people who are very similar in interests, actions, or appearance. Betty and Jennifer are as alike as two peas in a pod, so it's no wonder people sometimes mistake them for sisters.
(as) alike as (two) peas in a pod
phr. very similar. (The peas in a pod are essentially identical.) The twins are as alike as two peas in a pod.