AceShowbiz - Singer Shawn Mendes proved to be a good sport after be was subjected to an elaborate marriage proposal prank during a radio show appearance in the U.K. The "Treat You Better" hitmaker was chatting with Capital FM host Roman Kemp on Wednesday, April 25 when he was asked to help a listener, named Rob, propose to his girlfriend, Rebecca, on air.

The Canadian pop star eagerly agreed as he and Rob called Rebecca to pop the question. "I'm really nervous. I'm so excited though," Mendes said.

But the 19-year-old was quickly dismayed when Rebecca began to shout at Rob for proposing publicly and for involving a celebrity during what should have been an intimate moment. Mendes stepped in to comfort the jilted Rob following the incident, but his concern turned to laughs when he realised the entire awkward exchange was a prank.

"Roses are red, violets are blue," Mendes read from a paper Rob handed him. "Dear Shawn Mendes, we pranked you". As Shawn sighed with relief, Kemp commended him for maintaining his composure. The radio personality, who is the son of Spandau Ballet star Martin Kemp, said, "You did actually solidify yourself as the nicest man in pop".

The appearance was part of the Mendes' promotional tour for his latest single, "In My Blood".