HAProxy Unable to configure client certs for mTLS Backend app

Hello everyone,

I am doing HA Proxy setup, where our back-end application is configured for mTLS. I am having client certificates and key required for mTLS authentication with back-end application servers but being new to ha-proxy I am unable to find how to configure it.

OS: Amazon-Linux-2
Ha Proxy: version 1.5.18 2016/05/10

If possible we would like to hard code the client certificate and key to make every call to backend server to have client CERTS automatically.

HA-Proxy config

frontend http443
    bind                    *:443
    mode                    tcp
    option                  tcplog
    default_backend         app_servers_443

backend app_servers_443
    balance                 roundrobin
    mode                    tcp
    timeout                 check 10s
    option                  ssl-hello-chk
    server                  app_server    check inter 30s fall 3 rise 3

Thank you.