Just found a solution from the Microsoft website:
1. Start Outlook.
2. On the Tools menu, click E-mail Accounts.
3. Click View or change existing directories or address books, and then click Next.
4. Click Outlook Address Book, and then click Remove.
5. Click Yes when you receive the prompt to confirm the removal.
6. Click Add.
7. Click Additional Address Books, and then click Next.
8. Click Outlook Address Book, and then click Next.
9. Click OK when you receive the message to restart Outlook.
10. Click Finish.
11. Click Exit on the File menu to quit Outlook.
12. Restart Outlook.
13. In the Folder list, right-click the folder that you want to use with the Address Book (for example, right-click Contacts), and then click Properties.
14. Click the Outlook Address Book tab.
15. Click to select the Show this folder as an e-mail Address Book check box (if it is not already selected), and then click OK.