NEW YORK — From the drug dealing of “Weeds” to the sexual anxiety of “Spring Awakening.”

Hunter Parrish, who portrays Mary-Louise Parker’s oldest son on the popular Showtime TV series, joins the cast of Broadway’s Tony-winning “Spring Awakening” on Aug. 18.

Parrish will take over the role of Melchior, the thoughtful student heartthrob, from Canadian Kyle Riabko, who will headline the national touring company of the show. Riabko, a 20-year-old singer, songwriter and actor from Saskatoon, leaves the Broadway cast Aug. 2.

The show, based on Frank Wedekind’s classic drama, is set among the hormonally active yet sexually inexperienced youth of late 19-century Germany. It has music by Duncan Sheik and book and lyrics by Steven Sater.

Besides “Weeds,” Parrish has appeared in such movies as “17 Again,” “Freedom Writers” and “RV.” He will be making his Broadway debut in “Spring Awakening.”