Eclipse - which cost around 340 million euro - is the world's second largest private yacht and is the property of Chelsea owner Roman Abramovich.
It's not known whether Abramovich is on board the luxury vessel, which made waves in more ways than one when it sailed up the River Clyde just before 8am.
The yacht anchored at the Tail of the Bank and it's not clear how long she will be here for.
Eclipse has a crew of around 70 and has two helicopter landing pads.
Its passengers enjoy the benefit of 24 luxury guest cabins, two swimming pools, hot tubs and a disco.
She also carries a mini submarine.
Eclipse is not the only visitor to town today - massive cruise ship Eurodam is berthed at Greenock Ocean Terminal and due to leave later, at around 4pm.
Members of the public are reminded that departure times can change at short notice.
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