Meet Robin Thicke's Big Brother

Brennan Thicke, the eldest son of Alan and the brother of Robin, runs a medical marijuana dispensary. (AP Photo)

He's not the son of Alan Thicke who sings "Blurred Lines," and he's not the one who stars in Thicke's new semi-reality show, "Unusually Thicke."

Meet Brennan Thicke, 39. He's the older bro of R&B crooner Robin, 37, and the half-brother of 16-year-old Carter Thicke. Like Robin, he will only appear occasionally on Alan's latest TV venture, although Brennan already had the Web buzzing following the show's premiere this week. People wondered, just who is this mysterious other Thicke fellow?

[Related: Alan Thicke Show ‘Unusually Thicke’ Coming to TVGN]

Here are a few things to know about him:

1. Like his soul-singing sibling, Brennan is the son of the former "Growing Pains" actor and singer/actress Gloria Loring, who was on the soap "Days of Our Lives" in the '80s. (Carter's mom is Alan's second wife that he split from in 1999, former Miss World Gina Tolleson.)

2. Though the other Thicke men work in showbiz, Brennan has chosen a very different career path: He runs a medical marijuana dispensary called Venice Beach Care Center in Venice, California. Brennan's interesting occupation even plays a role in the show as Alan is having what he calls a "sex, drugs, and rock 'n' roll talk" with Carter. (Brennan is poised to face a similar dilemma one day, since he's the father of a young son.)

"In real life, Brennan owns a medical marijuana dispensary, a cannabis shop. It's completely legal," Alan told TV Guide. "The challenge is the great hypocrisy of how do you support one kid's business while at the same time telling the other one not to smoke weed? We do a whole episode about that."

3. However, Brennan has dabbled in entertainment. He worked as a voice-over actor as a teenager, playing the title character in the "Dennis the Menace" cartoon and voicing a role in a superhero cartoon, "M.A.S.K." He earned two Young Artist Award nominations for his work.

[Related: Robin Thicke Spends Birthday Partying With Leonardo DiCaprio]

4. Just like his parents, who co-wrote the theme songs to such TV shows as "The Facts of Life" and "Diff'rent Strokes,” and Mr. Blurred Lines himself, Brennan is musical. In 1999, he teamed with Alan, Robin, and New Kids on the Block crooner Jordan Knight to write a song called "Separate Ways" for Knight's debut solo album.

Unfortunately, the song wasn't exactly a hit. Good thing Brennan found his calling with cannabis.

"Unusually Thicke" airs Wednesdays at 10 p.m. ET PT on TVGN.