Gabrielle Union felt like her "beauty wasn't wanted" in Hollywood.

The actress, renowned for refusing to shy away from uncomfortable subjects, opens up about being a black actress in the new documentary 'Number One on the Call Sheet', and addresses a major issue that has long plagued stars of colour in Tinseltown - the unrealistic and unfair beauty standards they are often held to.

Gabrielle, 52, discussed her experiences in the show alongside other prominent black stars, including Angela Bassett, Halle Berry and Viola Davis, in the documentary's second episode - 'Black Leading Women in Hollywood'.

Directed by Shola Lynch, the episode delves into the barriers that have made it difficult for black actresses to secure leading roles.

It sees Gabrielle speak candidly about how black women with "coarse hair, melanin, thicker nose, wider nose, wider lips" are often excluded from the narrow definition of beauty in Hollywood.

She added about her battle with reaching stardom in Hollywood: "I started feeling invisible, like my beauty wasn't wanted.

"As a romantic lead? No."

Despite being widely regarded as one of Hollywood's most beautiful stars, Gabrielle says her talent didn't provide the same career opportunities her white contemporaries such as Amy Adams, Jennifer Garner and Gwyneth Paltrow, especially at the start of her career.

She added: "My look was appealing enough. But not so overpowering that it overshadows the white lead." Her early roles, such as in the 1999 teen rom-com 'She's All That', were often relegated to sidekick or supporting parts.

Gabrielle also highlighted a line from the '10 Things I Hate About You' script, which describes her character, Chastity Church, as "the less extraordinary, but still cute friend" to Larisa Oleynik's Bianca Stratford.

She said: "And so I was the perfect person to be 'the friend,' just left of centre of this white girl."

As Gabrielle's career progressed, she often found herself cast in supporting roles, playing the "b*****, sassy friend".

But her breakout role as the title character in the 2014-2017 BET TV series 'Being Mary Jane' marked a turning point, where she finally took the lead.

Shola spoke highly of the actresses featured in her documentary, saying, "These women represent a singular generation of Black leading actresses -- some of the best of the best.

"I had the great opportunity and responsibility of capturing all of their greatness into one documentary - talk about pressure."