The X Files star plays sex therapist, single mother Dr Jean Milburn in the Netflix teen comedy drama co-starring Asa Butterfield as her son.
Anderson, 51, appeared on The One Show on Monday night to discuss the launch of the second series and was asked about Sex Education’s runaway success.
4 days on since @NetflixUK released their highly-anticipated second series of #SexEducation , @gilliana is here talking all about her no-boundaries sex therapist character, Jean.— BBC The One Show (@BBCTheOneShow) January 20, 2020
Tune in to @bbcone now for Monday's edition of #TheOneShow. pic.twitter.com/hpiK9WCPUi
She said: "I'm not really sure whether I thought ahead. When I first read it, I had not really responded to it. I'd kind of put it in the bin, and my partner suggested I take it out of the bin and look at it a bit more seriously," she said.
"And actually when I did I found it incredibly hilarious, and kind of got what it was that they were after."
The actress - who is mother to two sons ages 13 and 11 - said she hopes the series will help encourage families to talk openly about personal issues.
She said: "To me that's one of the most important elements of the series, that it has so much heart and that it deals with very, very challenging issues that teenagers and families go through.
"So much of it is about communication. My character is awkward with the way she communicates or tries to communicate – she's completely over the top and inappropriate, even though she's a sex therapist.
"Her son is actually quite good at it and his modus operandi is to teach compassion, and forgiveness and communication and understanding – all things that are really wonderful to have in one's life, but can be quite hard to practice."
The first series of Sex Education - which follows Otis (Butterfield) and his classmates’ attempts to confront problems in their sex life - garnered praise from critics and several award nominations. Though filmed in Wales it emulates the style of an American high school drama, making it somewhat cuturally ambiguous to appeal to viewers around the world. It has just returned for a second series.