Botham, who will sit as a non-party-political crossbench peer, swore the oath of allegiance to Queen Elizabeth II as part of the ceremony.
England cricket great Ian Botham -- a vocal supporter of Brexit -- took up his seat in Britain's House of Lords on October 5.
He wore the traditional scarlet and ermine-trimmed robe for his brief formal introduction ceremony as a peer in the upper house of parliament, which is unelected.
Botham, who will sit as a non-party-political crossbench peer, swore the oath of allegiance to Queen Elizabeth II as part of the ceremony.
Lord Botham told the chamber: "I, Ian Lord Botham, do swear by almighty God that I will be faithful and bear true allegiance to Her Majesty Queen Elizabeth, her heirs and her successors, according to the law. So help me God."
Botham, who played 102 Tests for England between 1977 and 1992, is considered one of the finest all-rounders in the history of the game.
The 64-year-old, who became a leading commentator after he stopped playing, was knighted by the queen in 2007 for services to cricket and charity -- he has raised millions of pounds, mainly for leukaemia research.