Vocal powerhouse Adam Lambert has confirmed that this Thursday will be a huge day for him as he plans to make a big announcement live on television. 

Writing on his official Twitter page this evening (March 4), the 'Trespassing' superstar explained that fans should tune in to 'Good Morning America' later this week to catch the big news as it is unveiled. He wrote:

"I have a huge announcement to make this Thursday -- tune in to @GMA to find out what it is!! #AdamOnGMA."

Lambert, meanwhile, is still working as a cast member on hit U.S. musical drama series 'Glee' and recently opened up about the latest episode, 'Frenemies', in which he performed a rendition of 'I Believe In A Thing Called Love' by The Darkness: "This episode, I think it's just exploring the relationship of all the characters that are friends and hang out with each other, but are having some drama."

Listen to Lambert, Demi Lovato and Chris Colfer singing together on 'Glee' here: