Add extra number to my current pay monthly account

[Miguel1]

Hello there, I wanted to add my girlfriends number to my account, does anyone knows if is possible and how can i do it ? 

Thanks

[gmarkj · Accepted solution]

Log in to your My o2 using a browser, and look for the option to "bring in other products or services" to link the accounts.

Be aware that once you do this the only way to undo it is close one of the accounts, so bear that in mind @Miguel1 ...