Dion reportedly welcomed the fans as she entered the venue, where she and her late husband were wed in 1994, and was accompanied by her son Rene-Charles and 88-year-old mother, Therese.
"The whole funeral, that was all René's wishes, he obviously wanted to have his funeral where he married the love of his life," said a source.
"The support we've received has been such blessing," noted Dion.
Dion also took to Facebook the announcement on the live-streaming of her late husband's funeral.
"From anywhere across the globe, it will be possible to follow René Angélil's state funeral online tomorrow," Dion posted. "The broadcast will begin on Friday, January 22, 2016 at 3pm (EST) live from Notre-Dame Basilica in Montreal."
According to Daily Mail on Thursday, Angélil had to endure a long battle with his disease before finally succumbing to cancer just two days before his 74th birthday.
Angélil was was Dion's manager since the singer was a teenager, and were both married for 21 years, blessed with three children - Nelson, Rene-Charles and Eddy.
Dion will not be singing at her husband's memorial, but two of her songs will be played during the service as requested by Angélil himself, who also allegedly made preparations for his funeral so his wife will not be burdened.
After her husband's death, Celine Dion was seen for the first time boarding a private jet, along with her three children, en route to Las Vegas for a show in Caesars Palace, where the 47-year-old singer is a resident performer.
Dion's performances at the casino hotel are reportedly cancelled until the end of February, but the 47-year-old singer is set to perform on Feb.23.