By DAILY MAIL REPORTER
Doting father: Baby Olivia Marie rests on her father Lance Armstrong's chest as the family holiday in Miami
She may be his fifth child, but Lance Armstrong couldn't be prouder of newborn daughter Olivia Marie.
The cyclist tweeted a picture of the month-old baby today, writing: 'Hanging poolside with a beautiful little lady.'
Her head laying on his chest, Olivia looked to be listening to her famous father's heartbeat.
Keeping watch: Lance kept a close eye on both Olivia and his son Max
Despite her tender age, Olivia joined her parents and 17-month-old brother Maxwell Edward at the beach in Miami today.
Doting father Lance, 39, kept his precious youngster swaddled away from the sun in a protective blanket, keeping a close eye on son Maxwell as he played nearby.
The family unit was completed by their mother Anna Hansen, Lance's girlfriend of two years.
Daddy's boy: Lance carries Maxwell Edward on the beach
Anna and Lance met through his work with the charity where she works, First Descents, a non-profit that works with cancer survivors.
Both babies were born after Lance's battle against testicular cancer - which saw him return to full health after an initially poor diagnosis.
Lance, a seven times winner of the Tour De France, also has three older children from his marriage to ex-wife Kristin Armstrong - twin daughters Isabelle and Grace, nine, and son, Luke, 11.
Family day: Lance and his girlfriend Anna dressed for the sunny weather
source: dailymail