Hayden Panetteire‘s estranged mom says it was no real secret the actress was bisexual … and she’s questioning the timing of her daughter talking about her sexual preferences.

Hayden publicly came out as bisexual this week in an interview promoting her new memoir.

Her mother, Lesley Vogel, — again, estranged — ripped Hayden in an interview with The Daily Mail, saying … “I do not believe it was being hidden, but there is no historic proof that this is the case.”

Hayden told Us Weekly her book dives into how she started dating women at a young age — admitting she felt more drawn to them than men … but back then, she says the pressure to stay perfect in Hollywood kept her quiet.

Lesley also questioned the timing of Hayden coming out, telling DM … “I do think the timing of this coming out is very interesting.”

The timing makes sense when you think about … Hayden’s promoting a new book, and she grabbed headlines by sharing her truth.