The former American Idol runner-up will appear in the upcoming fifth season of the hit Tv musical, which takes place in a high school.
Glee co-creator Ryan Murphy confirmed the news on Wednesday (10Jun13) by tweeting, "I am thrilled to announce that the super talented Adam Lambert is joining the cast of Glee this fall."
Murphy did not reveal what part Lambert will play, but the pop star has previously voiced his appreciation for the show and admitted he would love to play himself in the singing series.
He said, "Glee is really irresistible - it's charming... (It) really paints a picture of what it's like to be an arts kid in high school."
Lambert isn't the first former American Idol contestant to appear on Glee - last year's (12) runner-up Jessica Sanchez had a guest role as a rival singer from another school.