Glass tumblers, a gift from Stephen Colbert to Jacinda Ardern and her fiance Clarke Gayford.

American television host Stephen Colbert has given Prime Minister Jacinda Ardern and her partner Clarke Gayford an engagement gift.

Gayford shared a picture of the etched "His and Her" glass tumblers.

"And by 'His and Her' I mean one says 'Mr' and the other says 'Prime Minister of New Zealand and Leader of the New Zealand Labour Party'," Gayford wrote on Instagram.

Stephen Colbert enjoyed a Kiwi barbecue with Jacinda Ardern, Clarke Gayford and Lorde.

"These are going straight to the pool room."

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Colbert dedicated an entire week of his popular late night talk show to screening clips about his recent visit to New Zealand last week.

Colbert interviewed Ms Ardern and went round to her house for a "New Zealand state dinner" with Lorde where they ate sausages and white bread. Colbert also offered to officiate her and Gayford's wedding.

Google had seen a spike in searches for New Zealand thanks the fun pieces on Colbert's show last week, Gayford wrote.