The 47-year-old performer hid her face behind a black veil but it was clear she was distraught and had tears in her eyes in a video shared by Global News.
Angélil died of throat cancer at the age of 73 on January 14. His funeral will be held on Friday at the same basilica.
Despite her grief, the star told People magazine that she was thankful to those who have kept her family in their thoughts at this tragic time.
Celine's husband in the open casket as sympathizers mourned
Also at the service was her mother Thérèse, 88, and René's brother André his sons Patrick and Jean-Pierrem, daughter Anne-Marie Angelil as well as Celine's eldest René-Charles, aged 14, who is namked after his late father.
The beauty made sure her makeup was done nicely as she greeted fan after fan with a handshake and sometimes a kiss. By the performer's side was her eldest son with Angélil - René-Charles, who wore a dark suit and tie.
Celine grieves at the open casket
The A New Day Has Come chart topper was seen approaching the casket where René laid peacefully. Her head was down and she seemed to be on the verge of tears.
Celine and Rene's oldest son Rene Charles Angelil attending the memorial ceremony
More people condoles with Celine at the open casket
The beauty's red tresses were pulled back into a ladylike bun. Hundreds of people attended the service. It is believed Angélil's adult children from a previous relationship - Anne-Marie, Patrick and Jean-Pierre - were also there.
'There are no words. She's in extreme grief right now. She's extremely heartbroken. But she's putting on a brave face.'
Celine welcome more people who condoled with her
In the last year 'the singer rarely left her husband's side' as he used a feeding tube, People added. 'He had both good and bad days,' a source said.
'Some days he could get up and walk around the room, play with the kids. Some days he was too tired.'
In the early years of their relationship: Celine (center) with René (left) and Eddy Marnay (right) in 1985
'We were all touched by the death of René Angélil,' Couillard said. 'Quebecers will have a chance to pay tribute to a man who had an impact on the cultural landscape of our nation.'
The church also was the location of their happiest day: The two wed at the basilica in December 1994
The couple are superstars in their native Canada and the funeral will be televised on three networks, according to TMZ. In accordance with Rene’s wishes two of Celine’s songs will play during the service. The Canadian beauty will not sing at the memorial.
Anne-Marie Angelil, Rene's daughter, left with with her husband Marc Dupre, who lovingly held on to her hand
Celine's mother Thérèse Dion, 88, joined the mourners