Facinelli, 41, proposed to Alexander (Thor, Marvel's Agents of S.H.I.E.L.D.), 31, at the top of the Empire State Building on Monday, People reports.
The couple both worked on Nurse Jackie and also co-starred in the 2012 romantic dramedy Loosies, which Facinelli wrote and produced. They went public with their relationship in November 2012.
Facinelli was previously married to Jennie Garth, with whom he has three daughters. Their divorce was finalized in 2013.
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