Marston Hefner and Claire Sinclair at the Playboy Mansion in Los Angeles on April 30, 2011.
Marston Hefner, the 21-year-old son of Playboy don Hugh Hefner, was arrested in a Los Angeles suburb Sunday night for allegedly assaulting Playmate Claire Sinclair.
Authorities confirm to E! News that shortly before 11 p.m., cops were called to the couple's Pasadena home after receiving a domestic-violence call. Sinclair suffered minor injuries, according to police, and Hefner was taken into custody without incident.
Hefner was charged with battery on a spouse and released a few hours later after posting a $20,000 bail. (Hefner and Sinclair were not married but under state law a "spouse" can be considered a cohabitant.)
No court date has been set yet.
Sunday night, shortly before the incident, Sinclair retweeted a photo of her attending a Grammy-themed fundraiser at the Playboy Mansion with Hugh Hefner and several other Playmates.
In it, she wrote: "Had so much fun with you guys xoxoRT @hughhefner."
The younger Hefner was not in the photo.
Sinclair admitted last year that's she's had a "tumultuous" relationship with Marston.
Marston is Hugh Hefner's third child, and his mother is 1988 Playmate of the Year Kimberley Conrad.
In 2008, he spoke to GQ about growing up next door to the Playboy Mansion, telling the magazine, "Well, as a 15-year-old kid, seeing naked people occasionally, that's -- it's just the lifestyle of growing up as Hugh Hefner's son, in his shadow. It's not a boo-hoo sob story. But it's not the same as every other kid."