The Thick of It actor, who was found guilty of the offence in 2007, will feature alongside Simon Amstell in Black Pond.
Langham told the Radio Times: "I was just grateful for the opportunity to work. That the script was brilliant and the creative team so talented was an unbelievable bonus.
"If people think I should do longer of not being allowed back in the room, as it were, then that's not my choice, it's their choice, and I have to respect it. Some people will think it's probably not an idea to be in my orbit until the dust settles and it's all right."
Directors Will Sharpe and Tom Kingsley confessed that Langham took part in the project for a "modest fee".
Sharpe explained: "We thought, 'Chris is perfect for the part, so why not? Presumably he's not been inundated with offers and he'll do it for a modest fee'."
> Chris Langham: 'I'm very sorry I offended people'
Watch the trailer for Black Pond, which is released on November 11, below (adult content):