Spotted stopping by the designer’s Belgravia store earlier in the evening, Gaga later emerged wearing the large feathered fascinator, much to the delight of waiting fans.

ON THE TOWN: GAGA CHANGED TO PARTY AT THE BOX IN SOHO (PICTURE: REX)REX

Before her night out on the town, the star – real name Stefani Germanotta – had been mingling with royalty at the Royal Albert Hall.

Ahead of her performance with Tony Benett, Gaga chatted to the 30-year-old prince, who couldn’t seem to take his eyes off her.

MINGLING: PRINCE HARRY COULDN’T TAKE HIS EYES OFF LADE GAGA (PICTURE: ALAN DAVIDSON/DAILY MAIL/PA WIRE)

Gaga told the Prince: “We are so happy to be here tonight and be of any help.”

Explaining how he and Gaga collaborated on their album, Cheek to Cheek, veteran crooner Bennett, 88, said: “I heard her personally and said we have to get together.”

Harry said: “I can’t believe you have the energy I don’t know how you do it.”

But Gaga laughed and replied: “He runs circles round me. Wait until we get on stage.”

She added: “We think you are fantastic. And thank you for bringing it here so we can support you.”

Bennett told the Prince he was friends with his late mother Lady Diana.

He said: “Your mum was a good friend of mine. I did many benefits with her.”

Harry replied “That’s fantastic.”

The concert raised more than £100,000 to support the charity.