The surprise visit by Scottish secretary Michael Moore came following an invite extended by hospice chief executive Dorothy McElroy during a fundraising dinner held in memory of the late MP David Cairns.
The former Greenock and Inverclyde MP was one of the hospice's biggest supporters and it is one of the charities to benefit from a foundation set up in his name.
The busy secretary of state for Scotland was so touched by what he heard about the hospice that he decided to pay them a visit.
Hospice chief exec Dorothy said: "We are absolutely delighted that Michael Moore agreed to visit us.
"We never imagined that he would respond to a throwaway comment about 'popping in for a cup of tea any time you're passing our way'.
"That he did so is greatly to his credit, and much appreciated by everyone associated with the hospice."
The David Cairns Foundation recently handed over nearly £10,000 to the hospice, with the money set to help fund vital programmes run there, including counselling for bereaved children.
Se up by Mr Cairns's friends, family and former colleagues, the foundation aims to create a lasting legacy from the MP's work.
Secretary of State Mr Moore said: "I congratulate everyone involved with Ardgowan Hospice on the sterling work that they do.
"The overwhelming ambience is one of compassion and care in a homely environment.
"I wish them well in the future as they continue to provide exceptional levels of service and care for the people of Inverclyde."
Last year the hospice - which has led the way in in palliative care and living with life threatening illnesses - celebrated its 30th anniversary.