Canadian groom sings tum hi ho for his Indian bride.

When Canadian Frank Gregoire married his Indian bride Simran Malhotra on June 27, 2015, he had a surprise waiting for her at the reception — one that took him six weeks of secret practice to pull off.

Gregoire, 36, from Sherbrooke, Quebec, sat at the piano and sang "Tum Hi Ho," the beloved ballad from the 2013 Bollywood film Aashiqui 2, for his new wife. Malhotra, 27, from Toronto, dissolved into tears of happiness — as did her parents and relatives.

The couple had met at work in 2012 in Baltimore, Maryland, where they now live — she was beginning her medical residency, he was starting a job as a critical care physician. For their interfaith ceremony, they exchanged vows under both Sikh and Christian traditions.

Gregoire had originally planned to read an original poem for his wife. But when he approached Simran's mother for ideas, she suggested a few songs — one of them "Tum Hi Ho." Once he read the translation, he knew he had found the perfect words. He spent six weeks learning the Hindi lyrics and the piano chords.

"My heart sank when I first heard him sing in Hindi. It was a feeling I had never felt before," Simran told Huffington Post Canada. "The only thing I was thinking was, 'How did he manage to do this?' I was the only one at the reception who knows how hard he truly works."

The video, captured by AVP Studios, went viral — a Westerner learning Hindi film music to honor his Indian partner touched millions.

Watch the video here.