Oprah Winfrey has interviewed countless famous figures over the years — from U.S. President Barack Obama to Holocaust survivor and Nobel laureate Elie Wiesel — but she admitted to taking a moment to collect herself before her most recent high-profile chat: the interview with Lance Armstrong.

"I prayed before doing that interview," the talk show guru told CBC's George Stroumboulopoulos during one of her recent speaking engagements in Western Canada.

During their discussion, Winfrey shared thoughts on a variety of topics with Stroumboulopoulos. (George Stroumboulopoulos Tonight)

"I sat in silence before going upstairs to do the interview and my prayer was that the presence in me would find a way to reach the presence in him — that I would create an open field," she said.

"I said at the beginning of the interview, 'it's an open field, I can ask anything I want.' I wanted to create an open field so he would have the space to be truthful, if that's what he chose to do, and that I would have no judgment of it."

Stroumboulopoulos conducted onstage interviews with Winfrey during each of her sold-out tour stops last week — in Edmonton, Calgary and Vancouver — and filmed an exclusive chat with the broadcasting icon for his show.

During their discussion, Winfrey shared her thoughts on a variety of topics, from her interview with the disgraced cycling star to celebrating her 59th birthday on Tuesday to American society's tendency to tear down celebrities.

"We're a culture — you are not, you Canadians. I don't put you all in that. Even looking at television here, television is calmer here. I don't see a lot of the nastiness I see on [American] TV shows — We just like to complain about things," Winfrey said.

"The only difference between famous and not is that more people know your name. Because, as you all can see, I'm just like you, except you know my name," she said.

So, regarding the recent controversy over whether singer Beyoncé Knowles sang The Star-Spangled Banner live or lip-synched to her pre-recorded track for the U.S. presidential and vice-presidential inauguration, "it was her voice," Winfrey said.

"I can see if she was using Mary J. Blige's voice, Alicia Keys' voice [you might be upset]. It was her voice. Why is everyone so upset about that?"

The full interview with Winfrey airs Wednesday at 7p.m. (7:30 p.m. NT) and 11 p.m. (11:30 p.m. NT) on George Stroumboulopoulos Tonight.