Is Optimism on MetaMask?

Could you please clarify for me if Optimism is integrated with MetaMask? I've heard rumors that they might be collaborating, but I haven't been able to find any official confirmation. I'm particularly interested in understanding if MetaMask users can seamlessly interact with the Optimism network for transactions and smart contract deployments. Is there a specific step-by-step guide or tutorial available for this integration, if it exists? Also, I'm wondering if there are any known limitations or challenges that users might encounter when using MetaMask with Optimism. Your expertise in the cryptocurrency and finance field would be invaluable in answering these questions. Thank you!