Siegfried and Roy Pet Baby Tiger in Vegas

Siegfried and Roy shook off any of the jitters you might expect them to have -- and snuggled up to a new arrival at The Mirage ... a baby tiger.

The magic duo bottle fed the little big cat in Vegas on Thursday ... as they returned to the resort where they famously performed for years, and where Roy was nearly killed during a tiger attack.

Clearly, no hard feelings. Plus, it's impossible to resist adorable baby tigers.