Need ETH in Base network wallet. Have WETH in Mainnet wallet, but no ETH. How can I swap it?

Sorry for the noob question. I have no ETH in either my Base wallet or Mainnet wallet, on Metamask. I need some ETH in my Base wallet in order to pay a transaction fee. My mainnet wallet has WETH in it, but if I try to swap on Metamask it says I need ETH for gas. Can I somehow easily use this WETH to get ETH into the Base wallet?