Kourtney Kardashian cuts a casual look in all white after dinner with son Mason at Nobu Malibu

Kourtney Kardashian has been getting serious in her relationship with Travis Barker.

And the Keeping Up with the Kardashians star’s kids have also become inseparable with his children.

She cut a casual look Monday in all white, as she stepped out after having dinner with her oldest son Mason and some friends at popular celeb hotspot Nobu Malibu.

Dining out: Kourtney Kardashian cut a casual look Monday in all white, as she stepped out after having dinner with her oldest son Mason and some friends at popular celeb hotspot Nobu Malibu

The 41-year-old sported a white denim jacket, which she paired with some matching high-waisted pants.

She layered the jacket over a grey top, which was tucked into her pants, finished with a pair of beige alligator skin stilettos.

Kourtney took precautions against COVID-19 in a brown face mask, as she stood in the parking lot with her group.

She hugged some friends goodbye as she stepped into the driver’s seat of her black Range Rover with Mason, 11.

White out: The 41-year-old sported a white denim jacket, which she paired with some matching high-waisted pants

White out: The 41-year-old sported a white denim jacket, which she paired with some matching high-waisted pants

Tucked in: She layered the jacket over a grey top, which was tucked into her pants

Hell on heels: It was finished with a pair of beige alligator skin stilettos

Hell on heels: She layered the jacket over a grey top, which was tucked into her pants, finished with a pair of beige alligator skin stilettos

Wear a mask: Kourtney took precautions against COVID-19 in a brown face mask, as she stood in the parking lot with her group

Wear a mask: Kourtney took precautions against COVID-19 in a brown face mask, as she stood in the parking lot with her group

Social distancing? She hugged some friends goodbye as she stepped into the driver's seat of her black Range Rover with Mason, 11

Social distancing? She hugged some friends goodbye as she stepped into the driver’s seat of her black Range Rover with Mason, 11

Casual outing: Mason rocked a neon green hoodie printed with skulls, grey sweatpants and a pair of beige slip-on sandals with white socks

Casual outing: Mason rocked a neon green hoodie printed with skulls, grey sweatpants and a pair of beige slip-on sandals with white socks 

Mason rocked a neon green hoodie printed with skulls, grey sweatpants and a pair of beige slip-on sandals with white socks.

Kourtney previously took to Instagram with an adorable throwback of herself napping with baby Mason.

She shares sons Mason Dash, Reign Aston, six, and daughter Penelope Scotland, eight, with ex Scott Disick, 37, whom she dated off and on from 2006 to 2015.

The Poosh founder made it Instagram official with boyfriend Travis Barker, 45, last month, after years of their close friendship.

Mama's boy: Kourtney previously took to Instagram with an adorable throwback of herself napping with baby Mason

Mama’s boy: Kourtney previously took to Instagram with an adorable throwback of herself napping with baby Mason

Co-parents: She shares sons Mason Dash, Reign Aston, six, and daughter Penelope Scotland, eight, with ex Scott Disick, 37, whom she dated off and on from 2006 to 2015

Co-parents: She shares sons Mason Dash, Reign Aston, six, and daughter Penelope Scotland, eight, with ex Scott Disick, 37, whom she dated off and on from 2006 to 2015

She posted a photo of their hands interlocked after the Valentine’s Day weekend, writing: ‘When friends become lovers.’

Barker also took to his Instagram Story with a hand-written love note from his girlfriend, which read: ‘To lots of fun adventures. May we destroy each other completely. Love, Kourtney.’

A source recently told People: ‘Kourtney is at a place in her life now where she’s ready for a relationship with a more mature guy. Her sisters love him.’

It's official: The Poosh founder made it Instagram official with boyfriend Travis Barker, 45, last month, after years of their close friendship (pictured in November, 2018)

It’s official: The Poosh founder made it Instagram official with boyfriend Travis Barker, 45, last month, after years of their close friendship (pictured in November, 2018)

Hand in hand: She posted a photo of their hands interlocked after the Valentine's Day weekend, writing: 'When friends become lovers'

Hand in hand: She posted a photo of their hands interlocked after the Valentine’s Day weekend, writing: ‘When friends become lovers’

Love letter: Barker also took to his Instagram Story with a hand-written love note from his girlfriend, which read: 'To lots of fun adventures. May we destroy each other completely. Love, Kourtney'

Love letter: Barker also took to his Instagram Story with a hand-written love note from his girlfriend, which read: ‘To lots of fun adventures. May we destroy each other completely. Love, Kourtney’

The insider added: ‘Kourtney and Travis have a long, long history and years of friendship. They’ve felt like family for years, and she’s really close with [Travis’ daughter] Alabama, who’s just a cool rock star kid.’

Travis recently gushed about their relationship on The Drew Barrymore Show: ‘I would date girls that didn’t have kids, and I find it kind of hard, because I think they have trouble understanding, well, “Why don’t you want to go to dinner every night with me?” or “Why don’t you want to see me every night?”

He continued: ‘And now, I’m spending time with a woman who’s a great mom, who’s a great friend, and you don’t have to worry about any of those things. It just comes natural.’

The Blink-182 frontman shares son Landon Asher, 17, and daughter Alabama Luella, 15, with ex-wife Shanna Moakler, 45, to whom he was married from 2004 to 2008.

Head over heels: Travis recently gushed about their relationship on The Drew Barrymore Show: 'I'm spending time with a woman who's a great mom, who's a great friend, and you don't have to worry about any of those things. It just comes natural'

Head over heels: Travis recently gushed about their relationship on The Drew Barrymore Show: ‘I’m spending time with a woman who’s a great mom, who’s a great friend, and you don’t have to worry about any of those things. It just comes natural’

Day with dad: The Blink-182 frontman was spotted running errands Monday in Beverly Hills with daughter Alabama, 15

Day with dad: The Blink-182 frontman was spotted running errands Monday in Beverly Hills with daughter Alabama, 15