I am trying to create Kafka topic with underscore with the below spec. I am getting the below error. Am i missing any parameter here?.

apiVersion: kafka.strimzi.io/v1beta1
kind: KafkaTopic
metadata:
name: my_topic
labels:
strimzi.io/cluster: my-cluster
spec:
partitions: 3
replicas: 1
topicName: my_topic

Error Message:
The KafkaTopic "my_topic" is invalid: metadata.name: Invalid value: "my_topic": a DNS-1123 subdomain must consist of lower case alphanumeric characters, '-' or '.', and must start and end with an alphanumeric character (e.g. 'example.com', regex used for validation is 'a-z0-9?(.a-z0-9?)*')