Mariah Carey bids $21,000 for shoes

The 'Shake It Off' hitmaker and the TV presenter - who recently renewed their wedding vows - splashed out on the footwear and the timepiece at an art fundraising auction to benefit the Urban Arts Partnership at the Opera Gallery in New York City last weekend.

Nick lodged the couple's bid - the highest of the night from any attendees - to clinch the purchase of the Project C.A.N.V.A.S shoe that was paired with a divers watch designed by Audemars Piguet.

Mariah and Nick both designed custom shoes for the event, with the brunette beauty's bling-inspired trainers selling for $2,000 - the highest price paid for a single pair of footwear throughout the evening.

Nick, who hosted the evening, went for a more urban look for his shoes, and singer Cee Lo Green, talk show host Ellen DeGeneres and rapper Swizz Beatz - who is married to Alicia Keys - also contributed footwear designs for the occasion.

The couple were spotted laughing and having a good time at the event, where they drank soft drinks and enjoyed music from DJ Mos.

Nick recently praised Project C.A.N.V.A.S - which stands for CAN Visually Achieve Success and promotes individuality and personality - saying: "It inspires originality for young people."