Not exactly but you can use the computer's ethernet internet connection via Wifi to the iPhone.
In that case just go to System Preferences > Sharing, then
- Select Internet Sharing
- Select Ethernet in the field Share your connection from
- Flag Wi-Fi in the field To computers using
- Go to Wi-Fi Options... and select a network SSID and a security password
- Click OK
- Flag Internet sharing
If you are using a pc with windows you can follow the instructions reported here. Basically:
- Go to Network Connections in your Control Panel by going to Start > Control Panel > Network and Internet > Network and Sharing Center and then click Change adapter settings on the menu on the left.
- Right-click your Internet connection that you want to share (e.g., Local Area Connection) and click Properties.
- Click the Sharing tab.
- Check the "Allow other network users to connect through this computer's Internet connection" option.