Plymouth winger Gregg Wylde will join League One side Millwall on 1 July when his Argyle contract expires.
The 25-year-old has agreed a two-year deal with the Lions, who lost in the play-off final to Barnsley last season.
Wylde scored seven goals in 51 games last term for Argyle, who were losers in the League Two play-off final.
"(Millwall manager) Neil Harris really sold the club to me and came to watch me play a few times too," Wylde told the club website.
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