The singer split from Russell Brand at the end of last year and their divorce was finalised in July.
Katy is said to be planning a celebration on what would have been her second wedding anniversary this week to avoid feeling unhappy in the build-up to her birthday.
‘Katy has been dreading October 23 for weeks now and has been trying to think of ways to turn it into something positive. It’s her birthday two days later and the last thing she wanted to do was spend that week depressed and miserable, which would then mean not doing anything to celebrate her birthday,” a source told British newspaper The Sun.
‘Her pals have been persuading her to have a huge party or go to Vegas for a few days but Katy decided on throwing a small gathering at her home.