A left-wing hopeful for the EU's top job took a seven-second pause when asked whether Russia should hand back control of Crimea.
Violeta Tomic, being quizzed on Euronews’ Raw Questions show on Tuesday afternoon, eventually said "I don't know" before calling for a second referendum.
The peninsula was annexed by Russia in 2014.
Tomic, from the Party of the European Left, said: “I don’t know because it’s their own issue. So I think they should make a referendum again.”
Officials said voters in Crimea overwhelmingly backed joining Russia in a first referendum in March 2014.
It was declared illegal by the EU and US and authorities in Kyiv said they would not recognise the result.