It’s another day, another mystery for you to solve — this time, we’ve got a smoking hot topless snap.

Can you guess this body-confident babe, lounging on the bed in some ripped jeans? Once you crack the case, you can dive into another set of NSFW babes stripping down.

Blake Lively has been targeted with a massive troll campaign amid her legal war with Justin Baldoni … her Instagram profile is flooded with porn.

A source with knowledge tells TMZ … Blake had no idea she had been targeted with the smut … and it’s now gone — her security settings have been updated.

Daniel Roberts, Meta spokesperson, tells us … “This kind of online harassment is wrong and we condemn it. We are removing the content that violates our policies and will continue to monitor for additional violating posts.”

It’s hard to know who started the porn posts – or exactly when, but they began at some point this month … hardly a coincidence amid her polarizing legal battle with Justin … the public taking sides. Worth noting Ryan’s IG was not messed with.

The dozens and dozens of porn posts went under the radar ‘cause they were under the “tagged” section of the app. That’s where anyone – even stars – can be tagged in a photo and it appears in their profile … unless specific settings are in place. Seems Blake with her 45 million followers didn’t have those settings on – but, she hasn’t needed them until now.

As you know … Blake filed a lawsuit against Justin last month — claiming he sexually harassed her on the set of “It Ends With Us” and then tried to ruin her reputation.

Baldoni has fired back at the claims, calling them totally untrue … before filing his own lawsuit against the Hollywood power couple — asking a judge to award him $400 million. He’s also suing the New York Times for a piece they ran after Lively filed her suit.

Darrell Feller, a retired U.S. Army National Guard pilot, is weighing in on the possible causes behind the tragic D.C. aircraft collision … sharing how a number of factors could’ve been at play.

We caught up with Darrell on “TMZ Live” in the aftermath of Wednesday night’s tragedy, and he explained how it was entirely possible the Army Black Hawk helicopter, which crashed into a regional jet carrying 64 people, didn’t even see the aircraft coming.

Darrell says the particular route the chopper took is known for causing “confusion with ground light,” due to the light from surrounding structures, buildings and other aircraft.

Darrell said this particular route, combined with the assigned runway, is known as the “most dangerous spot” … which means an incident is most likely to occur there — as it did this week.

While the route has been shut down by the FAA following the collision, Darrell made a case for its existence … explaining it allows Air Traffic Control a clear way to move aircraft in and out of congested airspace.

Darrell said something will have to be done about the danger zone … but shared it’s unclear if that means closing the tricky runway, or creating a new routing system entirely.

There’s currently a federal investigation into the cause of the collision … which left no survivors.