Jessica Simpson 'couldn't be happier' for her younger sister Ashlee Simpson

Jessica Simpson 'couldn't be happier' for her sister Ashlee Simpson after she announced she is expecting her third child.

Ashlee took to social media on Thursday to reveal she and her husband Evan Ross are expecting their second child together after four-year-old daughter Jagger, which will be Ashlee's third overall as she also has 11-year-old son Bronx with her ex-husband Pete Wentz.

And now, her older sister Jessica - who welcomed her third child, Birdie Mae, into the world 13 months ago - has said she's 'beyond elated', and can't wait to become an 'auntie of three'.

Happy sis: Jessica Simpson 'couldn't be happier' for her sister Ashlee Simpson after she announced she is expecting her third child. Seen in NYC in February

Happy sis: Jessica Simpson 'couldn't be happier' for her sister Ashlee Simpson after she announced she is expecting her third child. Seen in NYC in February

So close: Ashlee and Jessica in Venice Beach in 2015 with Eric Johnson in the background

So close: Ashlee and Jessica in Venice Beach in 2015 with Eric Johnson in the background

The 39-year-old singer - who also has Maxwell, eight, and Ace, six, with her husband Eric Johnson - commented on Ashlee's Instagram post.

'I couldn't be happier for my favorite person on the planet!!! This family of 5 over here are beyond elated for YOU, Evan, BX, and Jagger to expand the beautiful gift of family. Auntie of 3!!! This is hands down the most exciting news I could possibly imagine!!!' she said.

Ashlee revealed her pregnancy with a picture of herself and Evan holding up a positive pregnancy test.

So much love: 'I couldn't be happier for my favorite person on the planet!!! This family of 5 over here are beyond elated for YOU, Evan, BX, and Jagger to expand the beautiful gift of family. Auntie of 3!!! This is hands down the most exciting news I could possibly imagine!!!' she said

So much love: 'I couldn't be happier for my favorite person on the planet!!! This family of 5 over here are beyond elated for YOU, Evan, BX, and Jagger to expand the beautiful gift of family. Auntie of 3!!! This is hands down the most exciting news I could possibly imagine!!!' she said

Joyous: Ashlee and her husband Evan Ross had some great news to share on Thursday. The couple revealed to their Instagram followers that she is pregnant with their second child; they already have daughter Jagger, aged four, and she has 11-year-old son Bronx from her relationship with Pete Wentz

Joyous: Ashlee and her husband Evan Ross had some great news to share on Thursday. The couple revealed to their Instagram followers that she is pregnant with their second child; they already have daughter Jagger, aged four, and she has 11-year-old son Bronx from her relationship with Pete Wentz

Charity minded: She added: 'During this unprecedented time, we know pregnant women may be under greater stress which is why we are supporting @marchofdimes Mom and Baby #COVID19 Intervention and Support Fund

Charity minded: She added: 'During this unprecedented time, we know pregnant women may be under greater stress

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