She may not sit next to the President at public functions, and is not in the limelight much but within the Kibaki family and among friends and relations, Mary Wambui is no secret.
She is highly regarded as the Presidents second wife, and is accorded all the privileges due to a presidential spouse. She has been photographed with First Lady Lucy Kibaki and daughter Judy in London, and with Kibakis sons Jimmy and David, as well as with the Presidents father, Kibaki Githinji who died in 1983.
On every national holiday, the Presidents second wife who prefers to be called Mrs Wambui Kibaki arrives dutifully on time in the company of her bodyguards and quietly takes her seat on the dais, a few rows behind the President and First Lady. She is well known to the Presidential security and State House protocol staff.
On Friday, during the 40th anniversary independence celebrations, it was no different. She arrived without pomp or ceremony, in the company of her three bodyguards, and went straight to her unmarked seat on the dais.
Ever since President Kibaki won last years election, Wambuis Nyeri house on Ring Road, near Green Hills Hotel, has been guarded by administration police officers. She also has been assigned two bodyguards to escort her wherever she goes in her Peugeot 504 car.
The Sunday Standard has been compiling a profile of the Presidents retiring and publicity-shy second wife, and can now reveal that in Nyeri and Othaya towns, she is a well known and respected figure. Nobody there holds it as a secret that she is the presidents second wife.
In constructing her profile, the Sunday Standard interviewed her, together with members of the President's family several months back.
Wambui took charge of Kibaki's election campaign in Othaya Constituency, and Nyeri District, last year as he campaigned for the presidency countrywide.
Not that President Kibaki needed to campaign in Othaya but she handled all official elections business as his chief campaign agent, she revealed in an exclusive interview.
On the day Candidate Kibaki cast his vote in Othaya, Wambui was by his side, assisting him to vote.
At one time during the campaigns, she escaped unhurt when the aircraft she was traveling in crash-landed at Nyaribu airstrip near Nanyuki town.
Although Wambui was not with Candidate Kibaki when his car crashed into a ditch while returning from a rally in Machakos last year, she drove straight to the hospital when she heard news of the crash, and was among the first family members to arrive.
Wambui granted the Sunday Standard the first interview at her house, a palatial maisonette which she said had been bought by her husband.
She lives in the house with her daughter, Winnie Wangui Mwai, a Masters degree student and the only child she has with the President.
Leafing through the family album, she regaled our writers with memories attached to the numerous pictures she had taken with the Presidents family.
Why is so little known about her outside Nyeri?
Before Kibaki became President, says Wambui, even First Lady Lucy was not well known to Kenyans, as the President has never been one to involve his family in his political life.
She had assumed that on becoming President, she too, like Lucy, would be introduced openly, but it is an eventuality she is still waiting for. She thinks it might be that something to do with State protocol necessitated that there be seen to be only one First Lady.
Wambui says that at one time during the campaigns, before Kibakis accident, she asked him whether she should go public as his wife. The President, she claims, told her that she was not a secret, which she understood to mean that she would become part of his public life if he won the elections.
However, she says she is not bitter at not being introduced, and understands that maybe she should remain in the family and among Kibakis friends where she is known but not try to become part of his national image.
Wambui adds that she is consoled by the fact that even for President Jomo Kenyatta, Mama Ngina was the only First Lady even though his other two wives, Wahu and the late Edna, were officially recognised.
For a second interview we found her at Kibaki's expansive Naromoru ranch, which she manages on behalf of the family.
Despite her not being well known in public, she is part and parcel of the Kibaki family.
"I do not feel restricted, I have my time with him just as before he became President. I go to State House when I want and I can't complain. I am his wife and not being made public does not bother me," Wambui said in one of the interviews.
On the day President Kibaki officially opened the Ninth Parliament, Wambui was there but was kept company by the wife of State House Comptroller Matere Keriri, who is her long-time friend.
We had a short interview with her as we returned the pictures we had borrowed from her family album. She looked at ease as she mingled with dignitaries, several Cabinet ministers stopping to shake her hand as she joined the garden party at Parliament Buildings. But she did not go to sit under the official tent where the President sat with the First Lady to receive guests.
In the earlier interviews, Wambui said she had no problem at all with the First Lady. She has been increasingly operating from her Nyeri home while Lucy remains at the Muthaiga home.
Sources now indicate that Wambui has recently acquired a Nairobi home as she is in capital most of the time.
She said that in the earlier days, in the 1970s, she and Lucy often travelled together, even abroad, for shopping and other functions.
She says she is close to all the President's children, and makes it clear that she would not like to cause tension in the family or embarrass the President.
President Mwai Kibaki met Wambui in 1972 when she was a primary school teacher. Kibaki was at the time a Minister in the Kenyatta government. He was already married to Lucy, who had also been a primary school teacher in the early 1960s.
Wambui, who comes from Mahiga in President Kibaki's Othaya Constituency, says that she was introduced to her father-in-law, Githinji Kibaki, and to her brothers-in-law.
Some of Kibakis relatives have corroborated Wambuis statements from the interviews, such as the fact that she came into Kibakis life in the early 1970s.
Early in the 1980s, Kibaki formalised the marriage in a customary arrangement by visiting her parents at Mahiga and paying dowry.
One of Kibakis first cousins, Michael Kibaki, who grew up with the President, remembers the occasion when Kibaki met the customary requirement to marry Wambui.
"She is officially his wife and the family knows that," said the Presidents cousin.
In Othaya town, nearly everyone you would ask knows Wambui wa Kibaki as she is known in the President's village.
Soon after the General Election, she hosted a big party for all the Kibaki election agents while the President was still recuperating at State House.
Curiously, there are several media articles about her official functions in Nyeri, especially during the campaigns, but she is always only referred to by her maiden name, Mary Wambui.
She says that perhaps the media chose not to refer to her as Kibakis wife because it has never been stated officially.
"But take it from me, I am officially married to President Mwai Kibaki," said Wambui in another interview at Naromoru River Lodge.
Smart, tall, and articulate in English and Kiswahili, Wambui is of jovial mien even as she speaks of her life away from the limelight.
She talks extensively about Kibaki's private life and politics.
"I have known him for long, she says. Personally, he is a very humble man. The gentle manner you see him adopt while in public is the same manner he displays at home," she adds.
"He is a good husband and a good father to my daughter Winnie. He never quarrels even if you push him with words."
She says that when Kibaki left his former Bahati (now Makadara) constituency to vie in Othaya, she and Lucy worked with him in his first campaign there.
She says that she and Lucy took part in building Kibakis Othaya house in 1974 so that he could have a political base at home.
Later in the 1980s, Wambui became a Kanu official in Nyeri. She was often quoted in the media as a powerful Kanu official in the Nyeri office during the days when Kibaki was branch chairman.
She is a board member of several schools in Othaya and heads several womens organisations there.
Wambui could not divulge details about how she meets with the President because of state security concerns.
Apart from the Naromoru ranch, she is the manager of several other farming enterprises owned by the Kibaki family.