 During the second meteor shower , Lana witnesses the landing of an alien spacecraft , and two alien beings emerging and killing everyone in sight in the season five premiere . The spaceship becomes Lana 's primary focus in season five , officially teaming up with Lex Luthor to discover the mystery behind the ship in the episode " Splinter " . When her relationship with Clark hits a breaking point in season five 's " Hypnotic " , she begins to grow closer to Lex . The relationship with Lex eventually leads to marriage in the season six episode " Promise " , but not before Lana discovers Clark 's secret and realizes why he has been lying to her all these years . When she learns that Lex set up a fake pregnancy in order to get her to marry him in the season six finale " Phantom " , Lana effectively ends the marriage and fakes her own death to escape Lex after he threatens her . She also frames Lex for her murder , to punish him for his betrayal . It is revealed at the start of season seven that her effort fails , but as part of the " settlement " of their divorce , Lex makes sure that Lana does not go to jail for her actions . 
