'X-Men: First Class' Sky Ads Appear Over L.A. (Photo)

A loyal Heat Vision reader sent this in today while at a rooftop BBQ in West L.A.

The Xs have been popping up all weekend long, denoting a marketing blitz that will be kicking into high gear this week in advance of this Friday's opening of the X-Men prequel directed by Matthew Vaughn and produced by Bryan Singer (among others).

The movie has been earning rave reviews from critics including THR's Todd McCarthy, who compares it to the recent James Bond movie Casino Royale in how it reinvigorates the tired franchise.

"Roughly the first half of this massive and very well-cast origins extravaganza is arguably the best hour of Marvel Comics-derived filmmaking among the torrent of it that's cascaded across screens in recent years," McCarthy writes.

He al gives props to Michael Fassbender's turn as Magneto as a young man, Kevin Bacon as the villainous Sebastian Shaw and Jennifer Lawrence as Raven/Mystique.

Read his full review here and see what other critics have to say here.