João Manuel, Prince of Portugal
João Manuel, Prince of Portugal( 3 June 1537 – 2 January 1554) was a Portuguese" infante"( prince), the eighth son of King John III of Portugal by his wife Catherine of Austria, daughter of Philip I of Castile and Joanna of Castile.
As the heir to the throne he was styled Prince of Portugal.
Archduchess Maria Theresa of Austria (1862–1933)
Archduchess Maria Theresa of Austria  (18 September 1862, Alt-Bunzlau, Bohemia, Austrian Empire –
10 May 1933, Schloss Saybusch, Saybusch, Poland) was a member of the House of Habsburg-Tuscany and Archduchess of Austria, Princess of Tuscany by birth.
Maria Theresia was the eldest child and eldest daughter of Archduke Karl Salvator of Austria and his wife, Princess Maria Immaculata of Bourbon-Two Sicilies.
Sebastian of Portugal
Sebastian (20 January 1554 – 4 August 1578) was King of Portugal from 11 June 1557 to 4 August 1578 and the penultimate Portuguese monarch of the House of Aviz.
He was the son of João Manuel, Prince of Portugal, and his wife, Joanna of Austria.
He was the grandson of King John III of Portugal and Holy Roman
Emperor Charles V.
He disappeared (presumably killed in action) in the battle of Alcácer Quibir.
Sebastian I is often referred to as "The Desired" (Portuguese: "o Desejado") or "The Asleep"
(Portuguese: "o Adormecido"), as the Portuguese people longed for his return to end the decline of Portugal that began after his death.
He is considered to be the Portuguese example of the king in the mountain legend as Portuguese tradition states his return, in a foggy dawn, on Portugal's greatest hour of need.
Archduchess Maria Luisa of Austria, Princess of Tuscany
Archduchess Maria Luisa of Austria, Princess of Tuscany( full name:" Maria Luisa Annunziata Anna Giovanna Giuseppa Antonietta Filomena Apollonia Tommasa")( 31 October 1845 – 27 August 1917) was a Princess of Tuscany, and later Princess of Isenburg and Büdingen.
Joanna of Austria, Princess of Portugal
Joanna of Austria (in Castilian, "doña Juana de Austria"; in Portuguese, "Dona Joana de Áustria", 24 June 1535 – 7 September 1573) was a Princess of Portugal by marriage to John Manuel, Prince of Portugal.
She served as regent of Spain to her brother Philip II of Spain during his trip to England to marry Mary I in 1554-1556, and from 1556 to 1559.
She was the mother of King Sebastian of Portugal.
Afonso, Prince of Portugal (1526)
Afonso, Prince of Portugal was the first son of king John III of Portugal and his queen, Catherine of Austria.
He was the Prince of Portugal but died in the same year he was born, in 1526.
Archduchess Maria Luisa of Austria, Princess of Tuscany (1798-1857)
Archduchess Maria Luisa of Austria, Princess of Tuscany( 30 August 1798 – 15 June 1857) was a member of the House of Habsburg- Lorraine.
Isabel Osorio
Isabel Osorio( 1522–1589) was a Spanish courtier.
She was the long- term royal mistress of King Philip II of Spain.
She was the lady- in- waiting of empress Isabella of Portugal, Joanna of Austria, Princess of Portugal and queen Elisabeth of Valois.
She reportedly had two children with Philip.
She was rumoured to be married to the king, but this is not believed to have been accurate.
She is the subject of a novel," Isabel Osorio: El a mor secreto de Felipe II".
Otto, Duke of Brunswick-Grubenhagen
Otto, Duke of Brunswick- Grubenhagen( 1320 – 1 December 1398) was the fourth and last husband of Joanna I of Naples.
He also held the title of Prince of Taranto.
His nickname was Otto the Tarantine.
Andrew, Duke of Calabria
Andrew, Duke of Calabria( 30 October 1327 – 18 September 1345) was the first husband of Joanna I of Naples, and a son of Charles I of Hungary and brother of Louis I of Hungary.

Question: Who is Joanna Of Austria, Princess Of Portugal's husband?
Answer: João Manuel, Prince of Portugal