Is cat's pajamas the same as catnip?

Excuse me, but could you clarify something for me? I came across the phrase "cat's pajamas" and I'm wondering if it's somehow related to catnip. Is there a connection between the two, or are they simply two separate expressions with no direct link? I'm curious to know if there's a hidden meaning or if it's simply a case of two unrelated phrases that share a common theme. Thank you for your time.