West Mercia Police have released a picture of a man who may be able to assist them with their enquiries after the incident in Angel Place.
A man had approached the woman, wrapped his arms around her and kissed the side of her face.
The woman then moved away, only for the man to return minutes later, touching her shoulder.
The assault happened at 12.15am on Monday, September 16.
A spokesperson for West Mercia Police said: “We would like to identify this man as we believe he can help with enquiries into a sexual assault in Worcester on Monday, September 16.
“Officers are keen to speak to the man pictured as it’s thought he was in the area at the time and may be able to help with enquiries.
“If you know who this man is or have information that would help identify him, please email edward.bishop@westmercia.police.uk
“Alternatively, if you have information but don’t feel comfortable speaking to police, you can speak to the independent charity Crimestoppers.
“It is 100% anonymous. They never ask for your name, and they cannot trace your call or IP address.
“You can contact them online or by calling 0800 555 111.”