The MP pulled on a uniform and helped during a lunch-time shift at the Anchor Inn, in Malvern, to celebrate its re-opening following a fire.
The pub – which is owned by Punch Taverns – re-opened at the beginning of December, just in time to meet the Christmas rush.
Pub tenant Jayne Peters took Harriett on a tour of the premises and then invited Harriett behind the bar to pull a pint.
Anchor was 'missed while out of action'
Harriett worked in a pub while she studied at university.
She said: "It took me back to the university holidays. I know how much hard work is involved in running a pub.
"I was pleased to be able to celebrate the re-opening of the Anchor Inn and I hope they have a good and prosperous run-up to Christmas. The Chancellor has done his bit by ending the beer duty escalator.
"Pubs form an important part of our local community and I know the Anchor was missed while it was out of action. It is great news to see the doors open again."
James Lovegrove, Punch Taverns’ Partnership Development Manager for The Anchor, said: "It’s great to see a local MP supporting the pub industry. The Anchor is a great example of a pub at the heart of the community which sets high standards in all areas of the business and draws in customers from miles around."