(CNN) President Donald Trump said Saturday that he is considering granting a posthumous pardon to boxer Jack Johnson on the advice of actor Sylvester Stallone.

"Sylvester Stallone called me with the story of heavyweight boxing champion Jack Johnson. His trials and tribulations were great, his life complex and controversial," Trump tweeted. "Others have looked at this over the years, most thought it would be done, but yes, I am considering a Full Pardon!"

Johnson, the first African-American world heavyweight boxing champion, was convicted in 1913 under the Mann Act for taking his white girlfriend across state lines for "immoral" purposes. The Mann Act purported to prevent human trafficking for the purpose of prostitution, but critics have argued it was applied inconsistently to criminalize African Americans and those with dissenting political views.

Johnson was convicted by an all-white jury in less than two hours and was imprisoned for a year. The sentence and imprisonment destroyed the boxing career of the "Galveston Giant." He died in 1946.

In 2016, then-Sen. Harry Reid and Sen. John McCain , along with Reps. Peter King and Gregory Meeks, petitioned the Obama administration to grant a pardon to Johnson. The bipartisan group of lawmakers sent a letter to the White House asking that the pardon be given in honor of the 70th anniversary of the boxer's death.

Read More