Canadian pop star Shawn Mendes will forever regret missing out on the chance to chat to Meghan Markle and Prince Harry after losing his nerve at The Queen's recent 92nd birthday celebrations.

The In My Blood singer was wandering around backstage at the Royal Albert Hall in London last month (Apr18), when he stumbled upon the couple chatting in a room, and decided to say hi.

"Meghan's Canadian (sic), so I felt like, 'This is great, I can go and say hi'," Shawn tells chat show host Ellen DeGeneres. "I walked in with this confidence and the second they kinda felt me coming, I just turned around and my body went numb... I've never been so starstruck like that."

Mendes was so shaken by the near-encounter, he kept walking and missed out on an opportunity to chat to Harry and his bride-to-be, and wish them well for their upcoming nuptials, which take place at Windsor Castle in England on Saturday (19May18).

Meghan is actually American, although she lived in Toronto, Canada for years while shooting legal drama series Suits.

Meanwhile, the 19-year-old, who is half-British, also had an awkward encounter with the birthday girl at the bash, after she spent 10 minutes standing next to him.

"The Queen just walks up next to me and she's standing there and I'm looking at her and you can't say anything - you're not allowed to speak to her unless she speaks to you first," Shawn recalls. "It was like this very 10 minutes of just awkward silence (sic).

"She didn't look at me at all... It was super weird."