Martha Lane Fox, the founder of online travel website Lastminute.com, was appointed alongside Hugh Johnson, the vice chairman and chief financial officer of Pepsi.
Baroness Lane Fox, who previously lambasted internet industries as being controlled by “a bunch of very rich white men”, said that she “couldn’t wait” to start her new post and it was the “Best. Job. Ever”.
I’m joining the board of @twitter Thanks @jack @omidkordestani I can’t wait. Best. Job. Ever. Watch out silicon valley :-))
— martha lane fox (@Marthalanefox) April 8, 2016
Mr Johnston also posted his first ever tweet to mark the occasion.
Meanwhile two men, Peter Currie and Peter Chernin, will depart the board when their terms expire.
Twitter chief executive officer Jack Dorsey, who stepped into his role in October 2015, now has a 10-strong board which includes two women. He has promised additional roles on the board to improve diversity.
Welcome @Marthalanefox and @hughjohnston to the @Twitter board! And thanks to @plscurrie and @PeterChernin for all your years of service!
— Jack (@jack) April 8, 2016
The gender imbalance on the board has been a matter of contention for years.
Former publishing executive Marjorie Scardino was appointed in December 2013, two months after a board member made the joke that the company’s governing body must expand beyond “three Peters and a Dick”, referring to former CEO Dick Costolo and the all-white, all-male board.
After being criticized on this issue by Duke and Stanford University’s Vivek Wadhwa, Mr Costolo joked that he was the “Carrot Top of academic sources” and that there were much “bigger issues” than “checking one box” by having a quota of women on the board.
Mr Wadhwa replied that Mr Costolo had a “social responsibility. You have to lead- not make excuses.”
Twitter was founded just over 10 years ago and has not only struggled financially but has also faced difficult issues like users who tweet abuse and carry out anonymous trolling.
