Avengers: Age Of Ultron’s Robert Downey Jr. has a secret. Earlier today, Downey Jr. took to social media to let fans know that something big is happening tomorrow.

Downey Jr. wrote, “Seeing as how Tuesday is the most productive day of the week, I'll not decrease the efficiency. TOMORROW AM, however, I'll throw a surprise your way...”

Now, Downey Jr. is involved in a lot of projects, so there are a lot of things that the surprise could be about. However, it looks like Downey Jr. might have provided fans a clue. Check out the t-shirt that Downey Jr. is wearing under his jacket. It appears to be the same Black Sabbath t-shirt that he wore in The Avengers.

Of course, Downey Jr. is not the only Avenger to tease fans recently. At the end of August, Ruffalo teased that a video was coming soon that he wasn’t allowed to tell people about.

I made a video to tell you about a video that I'm not allowed to tell you about. https://t.co/maHuJYzF9F — Mark Ruffalo (@MarkRuffalo) August 30, 2014

Could they both be teasing the release of some sort of trailer or footage for Avengers: Age of Ultron?