Using Wildcard certificate for Traefik v2 in Kubernetes

I am trying to setup a combination of Traefik v2 as an Ingress Controller and cert-manager for validating and administrating my certificates.

What is the best way to use 1 Wildcard Certificate for all my Ingress resources?

I can't use the (by cert-manager created Secret) in all my Ingress resources because you can't cross-reference Secrets across namespaces.