The 68-year-old, who is married to Welsh-born actress Catherine Zeta-Jones, was attending prestigious film awards the Oscars last night when he heard of the Swans' 5-0 win over Bradford City at Wembley.
"Swansea won," Sky Sports News quotes Douglas as saying. "Very happy about that. Do you know how long it's been since Swansea have been at Wembley stadium? A long time."
The Welsh outfit will hold an open-top bus parade in Swansea tomorrow afternoon to celebrate their triumph.